BuddyPress Desktop Notification is a simple plugin that provides a desktop alert for any BuddyPress notifications that would normally be pretty much unnoticeable when only displayed in the site tool bar.
BuddyPress Instant Chat provides a one to one chat page for members of a BuddyPress social site. You use it by visiting the chat page, searching for the member you want to chat with, and then entering your chat message.
BP Avatar Hover is a simple plugin which adds the feature where if the mouse pointer is floated over a users avatar picture then a “bubble” of information will show up, showing that persons friends count, the avatar (and link to) three of their friends and also a link to send a message to that user.