Mozilla has released Firefox version 27.
As detailed in the release notes, the major new feature is support for the Firefox SocialAPI. Mozilla describes the SocialAPI as "a new API to make it easier for web browsers to integrate with social media services. Once a social service provider is implemented for Firefox, it becomes possible for the browser to display in-chrome user controls and information related to that service."
Three SocialAPI plugins are available today: Facebook Messenger for Firefox, Cliqz, and Mixi (Japan only). In the screen grab below of Facebook messenger for Firefox, you can see how the Facebook Messenger pane stays up and running while the main browser window is on another site.
Read more at: Firefox 27: Faster, more secure and more social | ZDNet