It stands for "Best BlackBerry Messenger Friend Forever"
1. A friend you are always messaging on BlackBerry Messenger because it's free and less pressure than calling, or you both prefer text to live talk. 2. Backup contact for late night texting and random chatting with to help make people think you are in demand. 3. Someone you like enough to talk to once in a while by instant message but not enough to get close with.
If someone says they are your BBBMFF it means they are TTH
Comes from BBM, BlackBerry Messenger app on BlackBerry phones, and BFF, as defined by the Paris Hilton show