The 'take me off this list' that took Microsoft down in 1997

1. In October 1997 a Microsoft employee sent a message to an internal distribution list called Bedlam DL3, thinking he was writing to his team: on the other end there were some thirteen thousand people. The first to reply to all asked to be taken off the list. The second replied to all to ask that people stop replying to all.

2. A third replied to all asking what Bedlam DL3 was.

3. Every reply landed in thirteen thousand inboxes and every inbox could generate another. Within hours some fifteen million messages were circulating, around 195 gigabytes, in a year when a home hard drive held two.

4. The company's mail servers went down. Technicians had to shut the system off in pieces to drain the queues before switching it back on.

5. Microsoft tells the story itself and left the name on it: the Bedlam DL3 incident. That is where today's limits at many companies come from: who may write to a large list, and how far a 'reply all' reaches.

6. Bedlam, in English, means madhouse, and comes from the Bethlem hospital in London. The name had been there from the start and nobody read it as a warning.