Microsoft today is celebrating the first anniversary of Lync 2010, the latest version of its unified communications solution. Lync 2010 is available as an on premise server, of course, but also as part of the wildly successful Office 365 cloud service.

In its first year, Microsoft has signed up nearly 3 million enterprise users for Lync 2010's telephony functionality, which they're using to replace traditional PBX systems.  And in the last fiscal year, Lync enterprise deployments grew 250 percent to 1.8 million lines, which, as Microsoft notes, is pretty impressive for a new product.

"We were excited about Lync, but you never truly know what you have with a product until customers really start to use it," Microsoft's Kirk Gregersen writes in a blog post announcing the milestone. "After reflecting on some of the stories we're hearing from customers, it is clear that Lync is indeed enabling people to communicate in new ways, increasing productivity wherever they are."

Customers say they're saving money by using Lync, too. LA Fitness reports an annual savings of $650,000, while Swisscom replaced 94 PBXs, resulting in a savings of $17 million across its 15,000 employees.

Lync is the latest version of a software solution that started life as Office Communications Server (and the associated Office Communicator client); I still using the 2007 R2 version for communicating with co-workers at Penton. With Lync, however, Microsoft has taken the concept of unified communications to the next level, with full PBX replacement capabilities. The client is pretty sweet, too, actually. I wish the guys responsible for Windows Live Messenger would take a few tips from the Lync client.

You can find out more about Lync 2010 on the Microsoft web site.