Pleas, read this article on WPCentral

[Xpider_MX]

Sharing is caring – How the Social Extensibility framework for Windows Phone 8.1 will make things better | Windows Phone Central

It explain a lot of things, new things in WP8.1, and can be applied to other aspects of the system, not only social functions.

 

[anon(7900571)]

It will be great to see if Rudy Hyun use the API for 6tag or whatsapp integrated in people hub.

 

[Xpider_MX]

It will be great to see if Rudy Hyun use the API for 6tag or whatsapp integrated in people hub.

It will be great!!

And remember that the apps (like facebook) are beta, and even if not beta, it can be get updates before WP8.1 launch.

 

[Jas00555]

It would be really cool if WPCentral would also integrate with the people hub too. I think it would be awesome to be able to reply to a private message from the people hub.