How to remove your FriendFeed account
Just use the link below and removal is on its way.
Direct removal link: http://friendfeed.com/account/delete
Helpful Trick: Removing online data
Helpful Trick: Remove third-party logins
If you signed up for FriendFeed using a third-party login such as Facebook or Twitter, you probably want to revoke all access from FriendFeed. Click here to find out how.