Activity streams aggregate all of your activities across a BuddyPress installation. All of your friends’ activities are also recorded so you can check what your friends are doing on the site. Enabled BuddyPress components make use of the activity stream component, which means any sort of activity can be recorded. Blogs posts, new friendships and blog comments are among the most popular activities recorded. Furthermore, custom components can also hook into the activity streams, meaning any sort of data can be tracked and recorded.