AOL Instant Messenger launched in 1997 and became how a generation of American teenagers talked after school — running-man logo, door-creak sounds, away messages left up for hours. Every IM window had a Warn button. Pressing it bumped the other person's warning level, a percentage shown next to their screen name; the higher it climbed, the slower AIM let them send messages, and at 100% they could be locked out for a while. The button was dropped in the mid-2000s with AIM Triton and AIM 6. AOL shut AIM down in December 2017.
