By scheduling a release in advance of Apple’s own OS X release, whose launch is scheduled for next month, it is clear that Skype remains committed to supporting Skype for Mac users.  With a customer base of 35 40 million concurrent users, slightly more than T-Mobile’s 33 million total customers, and substantially more than Vonage’s 2.4 million subscriber lines, Skype is quickly becoming one of the first choices in communication that people are moving to across all platforms.

This release isn’t heavy on flashy new features, but there are several new things Mac users will want to note. Here’s what’s new:

Additional Contacts Monitor Capabilities: This has been a feature enhancement that many Skype for Mac users have been waiting for. The ability to maintain a minimal interface and still have control over the contacts you can see.  You can view this feature by selecting Contacts Monitor from the Window menu.  No longer does the main window need to dominate the screen.  You can quickly see the online status of all of your Skype contacts organized into groups any way you like.

Ability to Turn Off Automatic Updates: Automated updates across a large user population who are all using the same internal network can be overwhelming to some network admins.  Not to mention managing multiple version differences from an internal help desk perspective.  Being able to turn off automatic updates can really help enterprise IT shops on both counts.

Improved iOS Video Call Support: If you have ever hosted a Skype video call between a Mac and an iOS device, you have noticed that Macs are landscape mode, and iOS devices can be either. The automatic detection is much improved in Skype 5.8, as it now fully supports portrait mode between iOS and Mac clients.  This may not be noticeable to everyone, but it does show that mobile to desktop communications is getting Skypes attention.

Group Screen Sharing for Premium Subscribers: In an effort to address all of a company’s communication needs, in addition to the already-supported group conference calls, you can now share your screen with those groups. Granted, it is limited to groups of 10, but that is likely a good number to support for the sort of impromptu meetings that this feature was designed to accommodate.  The best news is that only one member on the call needs to be a premium subscriber for all members of the call to take advantage of this feature.  This will help spread Skype usage by empowering power users in each social circle.

How does this compare to the version Skype is making for Microsoft’s own Windows platform? First, you shouldn’t try and compare the feature sets of the Skype client between Windows and Mac based on the version number alone. The Mac version of the Skype client has supported full HD video since version 5.3, released back in August 2011, whereas the Windows version just recently started supporting HD video calls with version 5.8 released in February.  Facebook integration has been part of the Mac client since the beta version of 5.4 was released in September 2011, which was about the same timeframe when the Windows version started supporting Facebook integration. Even the push-to-talk feature recently added to the Windows client has been part of the Mac client since the early beta of version 5.0.

For the most part, the feature set parity between the two clients has remained somewhat consistent by date, with the Mac version taking the lead on some features and the Windows version taking the lead on others. It is good to see that Microsoft is committed to the ongoing development of Skype on the Mac OS X platform.

This post was updated to reflect the most current number of concurrent users Skype supports.

Related research and analysis from GigaOM Pro:
Subscriber content. Sign up for a free trial.

• CES 2012: a recap and analysis
• Carrier IQ and the continued erosion of operator trust
• The future of mobile: a segment analysis by GigaOM Pro