We had something called Banyan Vines. It was an early LAN-based messaging system with few features. It did have one AWESOME feature, though, which was that you could send an anonymous message to another computer on the network. That message would pop up in the center of the screen in an official looking box with no indication of who sent it or that it was even from Banyan Vines.

At the time, we had loads of people who were quite new to computers. They were easily buffaloed by them, too, and here was a way to send official looking messages incognito. Hilarity ensued. One director, who could barely operate a mouse, decided to teach a staff biologist (who couldn't even find the mouse) how to move into the modern age by writing an email. They sat down together and spent a couple hours carefully crafting a response to some technical issue with regional ramifications. Not a casual endeavor at all. At one point, a message popped up in the center of the screen saying that the network would be going down in 20 minutes. About five minutes later, a second message popped up saying that the network would be going down in 10 minutes. A minute after that, a message popped up saying that the network would be going down in 5 minutes. At that point, they panicked and shut off the computer....without saving their work, whereupon the guy in the next office popped in to ask if they'd gotten his 'messages'.