Microsoft announced Lync-Skype connectivity in late May on the Lync Team Blog. This connectivity bridged their Lync enterprise collaboration tool with their free Skype voice and messaging network.
Both applications share some overlap in features:
Instant message chat Computer-to-computer voice calls Computer-to-LAN line (telephone) calls Computer-to-computer video calls Conferencing
However, each application is targeted toward different audiences. Lync remains a business-focussed platform companies can maintain on their own network or with a hosting provider. Skype . . .
Continue Reading: Connect Office 365 Lync for Mac to Skype