As we head into South by Southwest (SXSW), it’s clear the star of the show this year will be the group, replacing location services as the new kid on the block over which everyone will fawn. Groupon led the charge, of course, with a meteoric rise  in the public consciousness fueled by massive valuations, a Google takeover bid, and a disastrous (or ingenious?) Superbowl marketing campaign. A slew of group-buying website copycats followed, but the group trend wouldn’t remain limited to the retail sphere alone. Groupon was born on the web, but quickly went mobile with apps for both iOS and Android.

Path made a stir when it introduced the concept of sharing photos with an extremely limited circle of close contacts — essentially, a 50-person-strong group. Groupon used the group as clique, but an inclusive one where membership depended on your ability to recognize a good deal, which is subtly flattering to members of the group. Path represented a slight shift, making the group exclusive rather than inclusive, further emphasizing the clique feel. Like Groupon, Path managed impressive funding and garnered lots of publicity.

Lately, the group concept has exploded into a number of other areas, and combined with other hot mobile trends to create potentially market-disrupting hybrids. Convore got lots of attention for making web-based group communication incredibly simple and easy. So far, it has yet to develop a native iPhone or Android app to bring the experience to mobile devices, but the web-based version is solid enough for use on those platforms, and there’s an API and third-party solutions in progress.

If Convore doesn’t go mobile fast, it may find there’s no room left. Yobongo, a location-based group chat app for iOS that Ryan Lawler covered only a few days ago, is getting plenty of attention from the press and mobile device users. Yobongo adds a unique element by grouping users based on physical location. Stacey’s list of Austin-based startups to watch at SXSW this year includes a company with a similar app called HurricaneParty, and another with an app that aims to make group discounts more pertinent to where users are actually shopping.

Another location-based app looking to capitalize on the group trend is Ditto (which Ryan Kim covered just yesterday) which pairs location-based check-ins with your group of friends, allowing for quick and easy planning of impromptu get-togethers. Ryan Kim also covered RedRover this week, a location-based check-in service for close circles of friends who also happen to be parents. Both of these apps also contain a heavy dose of community-sourced recommendations, another app trend I’ve written about here at GigaOM.

In case you needed any further evidence that groups will be big for mobile apps in 2011, you need only look as far as Facebook’s recent acquisition of group-messaging app Beluga. Beluga provides users with the ability to chat privately, with the express aim of helping them plan outings or share info and photos. Sound familiar? It should if you’ve ever been a BlackBerry Messenger user. Shortly following the announcement of Facebook’s acquisition of Beluga, the possibility of RIM expanding the availability of BBM to other platforms was floated, suggesting the BlackBerry-maker isn’t eager to cede ground in this territory. But if Facebook does group messaging right, even a platform-agnostic BBM can’t compete.

Groups are hot, and not just because they’re getting a lot of hype. It makes sense for app makers to appeal to user groups instead of individuals, for reasons of adoption and relevance. A group-based app is likely to attract at least one more user for every individual it attracts, for instance, since users will want someone to use the app with. And if apps can attract users in batches, they can better evaluate the social matrix within which each one operates, making for more relevant personalized recommendations and more successful advertising and marketing campaigns. Users win, too, because the group provides continued usefulness for the apps in question, lessening the chance that a purchased or downloaded app will only get used or twice before being banished to the land of misfit software.

This year is the year of the group when it comes to mobile software. Developers, and users, need to ask themselves just one question: Are you in, or are you out?

Disclosure: True Ventures is an investor in Ditto, as well as in the parent company of this blog, Giga Omni Media. Om Malik, founder of Giga Omni Media, is also a venture partner at True.

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I’ve been using Ditto all morning, and I have to say that it’s excellent. Just like ClipCube, it’s unobtrusive and sits out of the way in the system tray until you need it, but it’s more powerful:

• Works with mouse or keyboard shortcuts/hotkeys (instructions are detailed here)
• Supports images, with thumbnails in the copied item list
• Unicode support
• Can keep multiple clipboards in sync over the network and send items between clipboards (with encryption)

Because it has more features than ClipCube, it’s more complex; some of its network settings may take a little figuring out, for example. However, its basic functions are very easy to use; I highly recommend it.

Ditto can be downloaded from Sourceforge. It’s available both with an installer and as a portable application.

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