Lync and Skype integration has been quietly available since at least March when Matt Landis posted about getting it working. Skype to Lync federation was available in a limited form around November 2012 with Skype 6.0 for Windows Live Messenger users who merged their Skype and Microsoft Accounts (previously Windows Live ID) but it did not allow for Lync contacts to be added to Skype after the migration Lync Federation will continue as Windows Live Messenger transitions to Skype.

sometime before September 2014 for video.

June 2013 for IM (Instant Messaging), presence and voice.

Timeframes for Lync to Skype integration were confirmed during the inaugural Lync Conference in February 2013:

Lync 2013 became publicly available without Skype integration which was a bit disappointing after being talked about as one of the many features.

Microsoft mentioned it in Lync 2013 Preview TechNet documentation (no longer available) and in a blog post by the Lync team UPDATE: Skype and so much more: Why we’re so excited about the new Lync which implied it would be available at launch. Skype integration with Lync has been teased since the first public beta preview of Lync 2013 in July 2012.

Skype sign up not microsoft account