Along with a whole new brand of applications to allow you to share your exact activities comes all new "verbs."  Since simply liking something just doesn't quite do it, they now extend to such goings on as "reading" a book, "watching" a show, "listening" to music, or even "cooking."  Developers can now coincide any verb with any noun to reduce the noise of likes into a natural set of activities, which you can customize what appears in your timeline.

The interesting concept is that realtime sharing allows for shared experiences as well.  Facebook is partnering with all sorts of content providing services: music services such as Spotify and video services such as Hulu.  These activities will appear in the ticker, showing what your friends are listening to/watching, giving you an opportunity to listen/watch with them.

It's like Xbox Live Party mode...just without the avatars and bad connection problems (fingers crossed on the latter).