Minecraft Social is a Social plugin for Minecraft that brings a friend management system to Minecraft. You can also view your player profile and friend's list.

Commands:
/friend help
/friend list
/friend add {playername}
/friend remove {playername}
/friend accept {playername}
/friend decline {playername}
/friend requests
/profile

Permissions:
minecraftsocial.addfriend
minecraftsocial.removefriend
minecraftsocial.acceptfriend