In addition to all the social features previously announced (and detailed) for the PlayStation Vita, Sony has announced that many popular social apps currently available on mobile phones will be made available for the Vita. Facebook, foursquare, and Twitter apps will all be downloadable for free directly from the PlayStation Store. In addition, Skype will also be making its way to the Vita, continuing Sony's support of the service since the PSP era. (Guess Microsoft's acquisition didn't get in the way, huh?)
In addition to cross-game chat and Skype, Sony has been experimenting with a number of other means of communicating with the Vita. For example, Sony showed off its own version of avatar chat:
We'll stick with Skype, thanks.