Blizzard and Facebook has announced a partnership, which will eventually let users stream a variety of the publisher's titles through the social network. No timetable for the implementation of this feature was provided with the official statement from Blizzard, but it'll begin sometime next month, when you can log in with Facebook when playing Blizzard titles.
The press release mentions Overwatch, World of Warcraft, Heroes of the Storm, Hearthstone, Diablo 3 and StarCraft 2 as upcoming supported titles. Here's a quote from the press release:
"Blizzard is in the process of incorporating Facebook's Live API in order to create its own "Go Live" streaming functionality for its games. When this functionality is implemented, players will for the first time be able to livestream their Blizzard-gaming sessions directly to their Facebook timelines, and friends will be able to subscribe and be notified when new streams are available."