one-minute
On AIM, when you IM someone right when they sign on, and their buddy info still says that they've been online for only one minute. Most of the time people wait until it says 2 minutes, to avoid feeling like a stalker.
Example:
Sally: Omg Jason just signed on and I totally one-minuted him by accident!
Kristin: =-O STALKER!!
Sally: Omg Jason just signed on and I totally one-minuted him by accident!
Kristin: =-O STALKER!!