Despite plenty of food in Second Life™, you will find very few bathrooms no matter how much you explore. And then the facilities are likely just for bathing. Thus the chat shorthand BRB can also stand for BathRoom Break.
Update 07 May 2008 02:24pm SLT: Found an actual bathroom with a toilet (SLurl). [14:20] Wicc Iris Door NT: You are not allowed to enter. Arggghhhh :::crosses legs and runs to RL::::