While the emergence of VoIP, or voice-over-Internet protocol, technology has already helped push down the cost of making a phone call, now it’s starting to have a deflationary impact on the world of mobile, where call charges remain stubbornly high.

In the meantime, the ongoing adoption of 3G broadband and the inclusion of Wi-Fi in many high-end phones is drawing a growing amount of attention to mobile VoIP services. Indeed, research firm Disruptive Analysis predicts that the number of VoIP-over-3G users will top 250 million by the end of 2012 — from virtually zero in 2007.

We at GigaOM are constantly tinkering with these mobile services, so we’ve put together a list of seven mobile VoIP apps that we think you’ll find handy.

Skype Options

Service: Skype Mobile
Platform/Network: Java-based application that works on 50 popular phones from Nokia, Sony Ericsson, Motorola and Samsung. Can be used on numerous cellular data networks.
Cost: Free
Features: Chatting (including with a group), presence settings (offline, online, do not disturb), and Skype-to-Skype calls (including SkypeIn).
Our Opinion: If your phone is supported, Skype Mobile is a great way to add Skype chatting and calls to it. Though it would be nice if the Skype application weren’t written in Java, as these applications are often sluggish and unstable.

Service: 3 Skypephone
Platform/Network: Uses a specialized handset. Currently available in the UK, Italy, Austria, Hong Kong, Australia, Ireland, Denmark and Sweden.
Cost: The phone costs £49.99 (about $98) and can be used on a pre-paid basis. Calls cost nothing if they’re made from Skype.
Features: Free Skype-to-Skype mobile calls and the ability to conduct Skype IM conversations, all without touching your computer.
Our Opinion: The 3 Skypephone is best suited for those who need a few monthly mobile minutes and wish to talk/IM to their Skype friends along the way. The pre-paid feature makes it an attractive and inexpensive option for Skype chatters in the geographies it serves.

Service: iSkoot
Platform/Network: Mobile handsets such as BlackBerry, Nokia, Windows Mobile and Palm OS models. Also works on GSM networks.
Cost: Modest to expensive, based on usage. Because iSkoot is a hybrid VoIP/GSM service, it uses SMS and mobile minutes when making and receiving calls or Skype IM messages.
Features: SkypeIn and Skype-to-Skype calls, Skype IM messages.
Our Opinion: iSkoot is a good option for keeping in touch with your Skype contacts. However, I would look at other software applications that just use data to send Skype SMS and Skype voice traffic.

Mobile VoIP Players

Service: Truphone
Platform/Network: Nokia handsets
Cost: Incoming free calls while on the Truphone network, low per-minute rates while on a GSM network. Outgoing calls are billed at very low per minute rates.
Features: Truphone offers free calls, SMS and voice mail while logged into the Truphone network via Wi-Fi. Otherwise, Truphone forwards calls to your mobile handset and you pay a low per-minute charge.
Our Opinion: With its smart forwarding options, Truphone is particularly useful for international travelers. Whether you’re on Wi-Fi or just your normal GSM network, you can be reached via your Truphone number no matter where you are (charges apply in certain cases, see their site for details). For times when Wi-Fi is not available, Truphone just released Truphone Anywhere, which utilizes local gateways for outgoing calls at low per-minute charges. I have trialed the service by forwarding calls from my Truphone number to my cell phone and the call quality was fantastic; voices were indistinguishable from any other cell phone call. A Truphone-to-Truphone VoIP call yielded even higher voice quality.

Service: Fring
Platform/Network: Nokia/Symbian handsets, Widows Mobile, iPhone (pre-release beta)
Cost: Free
Features: Allows you to make VoIP calls on any SIP network, Skype or to other Fring users. Additionally, Fring is a multi-protocol IM client that will allow you to chat with your buddies on Skype, MSN, ICQ, Google Talk, Twitter, AIM and Yahoo.
Our Opinion: I have used Fring to make SIP and Skype voice calls, and over EDGE the call is choppy and hard to understand. However, Wi-Fi provides enough bandwidth to make Fring calls clear and understandable. I wouldn’t say the quality is fantastic, but it is very comparable to a normal cell phone call.

Service: Talkonaut
Platform/Network: Available for Java-based phones, Symbian and Windows Mobile
Cost: Free
Features: Talkonaut offers free VoIP and IM chatting. For instant messaging, the application supports Google Talk, ICQ, AIM, and Yahoo. Talkonaut can also use SIP for VoIP calling.
Our Opinion: Talkonaut is a Russian offering and is still very new. The application was quite unstable on my Nokia N82 handset. With iffy performance and a very rusty user interface, I would recommend looking at other applications for this functionality, namely Fring.

Service: Nimbuzz
Platform/Network: Java program, Symbian; an iPhone version is coming soon.
Cost: Free
Features: Allows you to engage in IM conversations and conduct VoIP calls, as well as to share media such as photos and video. Nimbuzz also allows for client-to-client calls and has widgets enabling calls to originate from Facebok and MySpace. Compatible with Skype, Google Talk, AOL Instant Messenger, Windows Live Messenger, Yahoo, MySpace, Facebook and Jabber IM networks.
Our Opinion: The Symbian application is very responsive and easy to use. A VoIP call originating from my Facebook page to Nimbuzz over a Wi-Fi connection sounded good — just as good as any call over a GSM network.

Service: Gizmo5 (formerly Gizmo Project)
Platform/Network: Nokia Symbian handsets, BlackBerry, Windows Mobile, Nokia Tablets
Cost: Free for VoIP calls, low per-minute charge to call landlines and to SMS to mobiles.
Features: Gizmo5 allows you to conduct voice calls to other Gizmo5 users and grants IM conversations with friends on Gizmo5, MSN, AIM, Yahoo and Jabber.
Our Opinion: Gizmo5 is a great competitor to Skype, just not as established or well-known. They have wisely developed their client software for many platforms including numerous mobile phones, and on both Mac and PC. VoIP call quality is stellar when calling between clients, as well as to landline/mobile phones.

Just as any online content producer or web site owner is hungry for metrics about their web site, iPhone application developers are bound to want the same types of facts and figures surrounding the usage of their programs. New York City-based startup Pinch Media, which has received an undisclosed amount of funding from Union Square Ventures, First Round Capital and a handful of angel investors, offers iPhone SDK developers free code that gives them analytics based on unique users, active users and length of time the application is in use.

Not only has Apple has sold roughly 5.4 million iPhones to date, but it’s working hard to get the device into as many people’s hands as possible, launching it in country after country around the globe. At this point, it’s hard to gauge how large this market could become.

And with the iPhone SDK coming out in June at Apple’s Worldwide Developer Conference, we’re about to see an explosion of apps being offered by mobile developers. Indeed, as the iPhone ecosystem continues to evolve, startups that offer tools such as Pinch Analytics are going to be really valuable.

Strands, a Corvallis, Ore.-based startup that has shown success in the music social recommendation space, is relaunching Strands.com into a private beta online activity aggregation service. The company hopes to take the lifestreaming features offered by Web 2.0 darling FriendFeed a step further by adding the ability to build a “taste profile” based on your social media usage patterns.

Through the taste profile, Strands intends to battle the information overload from services such as Twitter and FriendFeed by using your online social circle to filter out relevant content you will find pertinent. “Hot Posts” will show you which online media items, such as news stories and videos, are currently popular among your friends to help you discover new things.

The company recently raised $55 million in capital and reports sales of $12 million in 2007. When I asked Jason Herskowitz, Strands’ VP of Social Media, how the company plans to monetize its new offering, he said Strands is merely looking for eyeballs to drive sales of its other offerings, such as Strands Social Player and Strands Business Solution.

I’m skeptical about how successful the new Strands.com service will be — it’s yet another service to sign up for and adopt. However, if implemented correctly, the service stands to bring the signal-to-noise ratio of lifestreams down to a tolerable level.

Phone makers these days are packing so many new technologies into their wireless handsets, it’s enough to make you nostalgic for a plain ole phone. Take Nokia’s N95, which has networking technologies including 3G and Wi-Fi, a still/video camera and a GPS module. But all of these features are pointless unless they’re easy to use and are stitched together in a such way as to fit into our daily lives. The best way to do this: software.

Nokia seems to be learning this lesson. A perfect example is Nokia Sports Tracker, which allows people to access statistics and other relevant information on their workouts. For instance, those who walk, run, cycle, or ski can track metrics such as average speed, total distance, altitude, and so on. By starting the application at the beginning of your workout, the program, through the use of GPS, tracks your positions and gathers statistics as you go. Sports Tracker’s latest version also includes the ability to include videos and pictures with your workout by attaching the media from your phone.

Nokia has also released a Sports Tracker beta web site that allows you to create a free account and upload your workouts from your handset directly to the web. There you can display a map of your workout route, average speed, elevation, and a host of other statistics.

But Sports Tracker isn’t just for fitness nuts. Travelers can share data about their trips with family and friends by way of a travel map accompanied by images and videos taken along the way. As Symbian-Guru has suggested, Nokia might want to consider a name change for Nokia Sports Tracker, something like Nokia Travels. Perhaps an integration with Dopplr is something the company should consider as well.

Strands, a social recommendation startup whose core product is focused on music, today made another move aimed at expanding into other areas with an agreement to buy NetworthIQ for an undisclosed amount. With the acquisition of NetworthIQ, Corvallis, Ore.-based Strands is looking to further build its moneyStrands personal finance application by giving users quality recommendations based on their entire financial portfolio. Competing personal finance startup Mint is similar in functionality, but only gives recommendations based on individual aspects of a user’s financial situation.

Todays news comes on the heels of Strands’ acquisition of Expensr, also a personal finance application. Over the last six months, funding for the four-year-old company has risen to some $55 million from investors including Spanish Bank BBVA, Grupo Zeta, Dabaeque and Sequal, so Strands appears to be using at least some of that money to try and replicate its success with music in personal finance.

Nimbuzz, a little-known mobile VoIP company out of the Netherlands, has released a mobile client that not only allows users to conduct VoIP calls, but to engage in IM conversations and share media such as photos, music and video. Nimbuzz, which claims to have received an undisclosed amount of funding from Skype’s original investors, Mangrove Capital Partners, seeks to utilize cellular data networks and provide users with an inclusive application for mobile IM and SMS communication.

With this service, Nimbuzz enters a market already dominated by established mobile VoIP clients Fring and TruPhone. Fring, like Nimbuzz, incorporates IM capability with multiple IM networks and VoIP calls. TruPhone allows you to make VoIP calls to TruPhone users and traditional phones, without the IM features of Fring and Nimbuzz. Back in January of 2007, we covered Nimbuzz and criticized the service for offering cumbersome (although cheap) VoIP-on-mobile minutes. With the addition of the desktop clients, social widgets and IM, however, Nimbuzz is a much more features-packed option.

To load Nimbuzz, download their client from their mobile web site, create an account and sign in. Signing in to additional networks such as Google or Yahoo is as easy as entering your username and password for those respective services.

Nimbuzz is very responsive and easy to use, featuring a great native Symbian user interface. A VoIP call originating from my Facebook page to Nimbuzz over a Wi-Fi connection sounded good — just as good as any call over the GSM network. And the laundry list of IM networks supported by Nimbuzz includes Skype, Google Talk, AOL Instant Messenger, Windows Live Messenger, Yahoo, MySpace, Facebook and Jabber.

Nimbuzz has a Java version of their mobile client to accompany the newly released Symbian version as well, and an iPhone version is in the works. Outside of their mobile offerings, the company has a Windows desktop application for conferring with your Nimbuzz contacts and social widgets that can be embedded onto your Facebook, Orkut and MySpace pages. By clicking on your Numbuzz widget, friends can call/chat you for free, leave you a voice message, send you a text message, and share photos, music, and videos with you. One word of caution, however: If you do elect to use Nimbuzz, you’ll want to have an unlimited data plan on your mobile device.

The iPhone’s ability to switch seamlessly between Wi-Fi networks and AT&T’s EDGE network with minimal mucking around by the user still remains unmatched. If you’re using one of Nokia’s increasing number of Wi-Fi enabled phones, the experience is the opposite: painful. Unless you permanently set a preference in each individual application, you’re annoyingly prompted to select a network whenever a program tries to access the Internet.

Nokia is still grappling with this problem. The good news is that there’s a fix: Psiloc Connect. Psiloc Connect works by creating a new Access Point on your S60 device. By pointing any application to the Psiloc AP, you can set your preferences so Psiloc will attempt to connect through Wi-Fi, then will try your cellular data connection next, whether it be 3G, EDGE or GPRS. In other words, with Psiloc, you can let the phone choose the fastest data network available. It will set you back about $16, which isn’t cheap — but I think it’s worth owning.

SlingPlayer Mobile has announced updates for their clients on Windows Mobile and Symbian S60 smartphones. The new SlingPlayer client adds support for additional handsets including the Nokia N95 8GB, Samsung i750 and Treo 500v, among others. The new clients support Sling’s newly released set-top boxes as well.

SlingPlayer Mobile is a mobile extension of the SlingPlayer service; it allows users to view content from and control their home television from their mobile phone. The upgrade to the new version is free if you already own SlingPlayer Mobile, otherwise the client can be had for a $30.

Updated: Whisher has sent this special offer to our readers. They are giving away WiFi Out credit to GigaOM readers, and you can get the details here. The deal allows you to get free WiFi at Starbucks, Hilton Hotels, International airports and other locations.

Whisher, which provides access to Wi-Fi hotspots around the world in exchange for access on users’ own home or business networks, has unveiled a client that allows access to its hotspots on Nokia Symbian (N81, N82 or E61) phones. The move is a smart extension of Whisher’s service offering; Nokia has been including Wi-Fi chipsets in many of its smartphones and has built a strong market share.

To integrate the client (and further lock users into using the Whisher service), the company has introduced a feature called Automatic Connection. When enabled, Automatic Connection scans all Wi-Fi networks within range and connects to the one with the strongest connection. (It’s unclear at this point whether the client would prefer a Whisher network over an open-access network if the two network strengths are equal.)

If you’d like to try the Whisher Wi-Fi sharing system and the associated Symbian client, there are two steps. First, visit Whisher’s web site and download the software appropriate for your home networking set-up (the company has both Windows and Mac clients). Once it’s installed, you’ll be “sharing” on the Whisher network of global Wi-Fi hotspots. Then point your mobile browser to http://nokia.whisher.com and install the Symbian application. After the app is installed, available Whisher hotspots will have a designated “W” icon attached, as pictured on the right.

To see whether the Whisher service has hotspots in the areas you frequent, be sure to view its global map.

The Wisher Wi-Fi network isn’t as far-reaching as the Fon network, but moves like this Nokia agreement — which capitalizes on the E Series and N Series wireless networking capabilities — are proof the company is working to stay competitive. What Wi-Fi roaming service do you use? Would you recommend it?

Jeff Pulver said today that he has resigned from the board of Pulvermedia, the company he founded. Pulver is a pioneer in the VoIP world and Pulvermedia — the company behind the VON conferences and magazine — has been a rallying point in the VoIP community.

As Om reported last month, rumors have been swirling recently that Pulvermedia was being shut down. TICC Capitol Group, which invested $11 million in Pulvermedia last summer, had expressed concern over its financial state and seized control the company’s bank accounts. It was believed that Pulvermedia and senior management was trying to make moves to stabilize the company, and Pulver leaving at this stage in the game is not a good sign.

Who knows what the state of Internet telephony would be without Pulver’s accomplishments. There are no details yet as to where he’ll land next, but I’m sure he’ll have something exciting coming down the pike soon.

(full disclosure: Our columnist Daniel Berninger is a long-time business associate of Jeff Pulver’s.)

As a new parent, I am constantly faced with the dilemma of how to best keep my extended family in the loop with regards to events in my daughter’s life. I could easily start a blog, on which I could post written updates along with images. But I would prefer not to have the entire web be “in the know” about what my family is up to; I really only want that information to be consumed by my close friends and family. I could password-protect the posts, of course, but that would create a barrier for the less technically savvy of my family members. And emailing photos and event updates just seems too…Web 1.0, for lack of a better phrase.

Enter Sampa. The service is best described as a secure, weblog-style site on which families can post events, videos, pictures and stories. And it was built with security and simplicity in mind.

You start by naming your Sampa site, creating a personal profile, and building the site’s look and feel. Then fill out your first post — whether it be a story, video, picture or other message — followed by the contact information of the friend/family member with whom you’d like to share it. They are subsequently sent an email containing a private URL to your post.

The barriers to adoption are low. With the private URL, Grandpa and Grandma don’t have to remember their username and password. Not do they have to constantly check the site for updates, because every time you update it, Sampa sends them an email.

If you’re seeking an easy-to-use content management system to run a web site, give Sampa a look. Their hosted solution is an attractive option for both the content creator and end user alike.

If the first five seconds of every cell phone conversation were recorded, researchers would probably find that many start with the phrase “Where are you?” Answering that question before it’s asked is the aim of a new location-based web application called sniff, which stands for Social Network Integrated Friend Finder.

A permissions-based application, sniff uses “a combination of GPS or other location technology” to let you to instantly locate your friends via one of two data sources: mobile phone or Facebook. Mobile users interact with the service by sending an SMS to sniff requesting a friend’s location; the Facebook app will “sniff out” multiple friends’ locations and display the results superimposed on a map.

According to Useful Networks, the company behind sniff, the service is very popular in Scandinavian countries. It will soon launch in both the UK and the U.S.

What about the creepy factor of being located by anyone at any time? According to Useful Networks, you have complete control over who can locate you and when. The company has built in different levels of privacy that would allow you, for example, to dictate that your co-workers can only locate you during business hours, but close friends can locate you in the evenings and on weekends.

Would you be willing to exchange location information with the people you know? Or does sniff sound too Big Brother-ish?

What separates the good from the bad in the mobile web space? More importantly, what makes a good mobile application truly great? There are lots of examples out there, but what can mobile developers learn from them? Here are some common sense guidelines:

Mimic the desktop UI

Each web site or web application that we use in this Web 2.0 world has a feel that we’re used to; the mobile version of web sites should merely be an extension of that experience. Web developers should use the same fonts, color schemes and buttons wherever possible to make us feel at home. For an example, check out Mobile Facebook (here on the left), which uses the same blue hues and fonts as the Facebook I use everyday in Firefox. Facebook has also made it easy to click on a friend’s name and pull up their profile page with a mini-feed, contact information, and other Facebook features we know and love.

Good examples: Mobile Flickr, Mobile Google Reader and Pownce Mobile.

Strip it, strip it real good

A great mobile web site is a stripped-down, more functional version of its original incarnation, and simplicity is king — all unnecessary graphics should be be excluded. In terms of screen flow, content should be presented first, with navigation placed at the bottom of each page. Having to scroll past navigation to get to the real meat of a web page is the bane of any mobile user’s existence.

Good examples: Mobile Twitter, Google and Mobile Wunderground.

It’s the hardware, stupid

Smart mobile application developers utilize the hardware to its full extent. One example is the Nokia platform, which is known for being completely transparent and vulnerable to developers and has subsequently yielded some great applications.

Good examples: JoikuSpot will use the built-in Wi-Fi to turn your WAP cell phone into a wireless access point; ShoZu will use the N95’s GPS to automatically geo-tag photos and upload them to Flickr; Nokia Sports Tracker will use the GPS module to give you a map and stats about your workouts.

Know thy platform

Mobile web applications should be written natively for each device. Java applications, including GMail for mobile and others, are quirky and routinely lock up, requiring the user to either exit or restart. Having to write apps for multiple platforms may be tedious, but will result in happy users.

Google was able to take Google Maps to an entirely new level of usability by adding “My Location,” which uses cell-phone towers to give an approximate location and has been called a “poor man’s GPS.” It’s only accurate to around 1,000 meters, but saves keystrokes when trying to find a local pizza place.

Unfortunately with most mobile platforms, especially here in the U.S., hardware is limited by cell-phone service providers that subsidize handsets. But Google’s Android and the Open Handset Alliance will help put in motion a new era of “openness,” and consumers will be the direct benefactors.

And of course, Apple’s SDK is coming out soon, which will undoubtedly spawn numerous touch-based applications.

My prediction: The iPhone will be the most hotly contested mobile application platform and the App Store will be full of highly functional and downright fun applications to add to your precious iPhone.

It’s hard to beat the utility of Google Calendar. The app allows you to share and collaborate your calendar with others, makes it possible to view colleagues’ schedules and availability, and generally keeps your hectic life in order.

Google Calendar would be even more useful if you could have mobile access to it. For BlackBerry users, there’s Google Sync, a tool that will seamlessly sync the BlackBerry calendar with Google Calendar. However for Nokia/Symbian phones, useful options are a little more difficult to find. But they do exist; below are three:

GCalsync

Gcalsync is a freeware java program that will sync multiple Google Calendars with your Symbian calendar. Unfortunately, this open-source project lacks an intuitive user interface. Downloading and installing is straightforward, but operation of the application is clunky at best. Each time the application is launched, you must grant it permission to your Symbian calendar, which takes a considerable amount of time and multiple keystrokes. The application does, however, allow for two-way sync, meaning an event you create on your smartphone will be uploaded to your Google Calendar and vice versa. But if an appointment is changed on your phone and the changed parameters are pushed to your Google Calendar, they won’t be reflected there. Also, time zones appear to be problem for GCalSync, with events getting slotted hours later or earlier than intended.

GCalSync shows some promise, but at this point it’s not ready for prime time. Om first wrote about this product back in October 2006; it doesn’t appear to have matured much since then.

Calsync60

A new entrant into the Symbian software market, CalSync60, is winning fans in the Nokia blog community. This S60 native application runs quickly and is dead simple to use. Download and install the application from their web site, enter in your Google credentials, and the sync process will begin. CalSync60 also supports two-way syncing and the application will set calendar item alerts as they are configured in your Google Calendar.

Keep in mind that CalSync60 is still in a beta testing period. However, the feedback regarding stability and performance has been positive thus far. CalSync60 recommends you back up your Google Calendar before attempting a sync with their application.

GooSync

GooSync is a commercial web service that comes in two flavors — free and premium. With the free service, you can sync only one Google Calendar and can only sync events 30 days out. The premium service, which is £19.95 ($40) a year, will allow you to sync contacts, set categories for calendar items and contacts, sync up to 365 days out, allow you to sync multiple calendars, and execute autosync.

To set up the service, go to GooSync and create an account. Through the sign-up process you grant GooSync access to your Google Calendar. You are then given access to the GooSync installer file for your Nokia phone. After installation and set-up, GooSync is an option in your Tools->Sync menu, making syncing quick and painless.

GooSync is by far the most seamless service. I have been using the free version and have found that it meets my needs. The most provocative premium service, in my opinion, is the ability to autosync. Having to manually initiate a sync is too time-consuming.

Even though there are options for syncing your Google Calendar with your Symbian handset, the process is still a bit convoluted. GooSync is the closest option Symbian users have to a seamless solution, if you’re willing to pay to use it. My hope is that with advancements in the API, more software developers will develop business-ready solutions for the Google Calendar syncing issue.

Apple today unveiled enterprise features for its wildly popular iPhone that will be available via a software update scheduled for release in June. With extended support for Exchange (Apple has become a full ActiveSync licensee), the iPhone will be able to receive push email, calendars, contact, address lists and other features, the company said during a presentation of the iPhone Software Roadmap. Other enterprise security features include WPA2/802.11X support, Cisco IPsec VPN, identities, certificates, and remote wiping of the device.

This is Apple’s (AAPL) attempt to take on the BlackBerry, the popular communications device made by Research In Motion (RIMM). The news helped push RIM’s stock down nearly 4 percent, even though it will be a while before the iPhone can become a real challenger to the Canadian company’s ubiquitous device.

Also today, marketing head Phil Schiller unveiled the iPhone software development kit (SDK), which will give outside application developers the same level of access to the iPhone’s capabilities as in-house Apple developers. The new API is called Cocoa Touch; it will support multi-touch events and controls, localization, alerts, the image picker, camera, and the accelerometer. There will also be an iPhone simulator for developers to test their code within a development environment.

Just as Apple granted us access to podcasts through the iTunes store, iPhone applications will be accessible through a new program called AppStore. Also due to be included in the upcoming software update, AppStore will display application categories including games, health, finance, lifestyle, just added and top picks that can be downloaded directly onto the device. Developers will be able to independently add their applications to the AppStore and price them however they want (including free), with 30 percent of the revenue going to Apple as overhead.

And finally, as the event was wrapping up, Apple demoed the iPhone’s gaming capabilities, including introducing a working demo of AOL Instant Messenger and a Salesforce application. Electronics Arts said it will be porting its popular Spore game to the iPhone as well.

Yahoo has unveiled a new personalized mobile web content management utility called onePlace. The tool, which will be launched in the second quarter of 2008 as part of Yahoo Go 3.0 (a previously announced mobile application that enables easy access to existing mobile Yahoo services), will be able to track on mobile devices emails, news feeds, web sites, videos, search queries and more.

This means you’ll be able to manage My Yahoo feeds, stock portfolios, Flickr photos and even keep an eye on YouTube, Digg, Facebook and many other sites. Marking content will be as easy as bookmarking it in a browser, according to a company statement. And all web content will be able to be tagged, allowing disparate items to be categorized in a flexible manner.

If onePlace is user-friendly, it will be a powerful force in mobile content aggregation. With Google and Microsoft starting to ramp up their mobile online offerings, this is one area where Yahoo needs to flex their muscle.