Lets members like posts. Each like is stored as a like comment on the post and appears in the BuddyPress activity stream, and likes are left out of the post’s comment count and comment notification emails. The number of likes is shown with the post’s content.
Logged-in members get a Like or Unlike button; logged-out visitors get a Like link that asks them to log in and completes the like afterwards. Themes can show it with the Like button block, for example in a post’s footer inside a Query Loop.