Identity theft on mailing lists

On Yahoo! Groups I am the moderator on a mailing list, where sombody suddenly got really active with advertising to sell something. Many people complained including the person whom everybody believed to be sending all the adverts to the list. The real person does actually sell those items, but only upon request, and not by aggressive advertising.

The investigation that followed the matter caused the identity theft to be discovered. The person who did that was banned and a message was sent to the members to explain what has happenend. Previously I have only read about this problem in various newsletters, but never actually encountered it yet.

What gave it away was a search for the name of the person, where the email address was quoted as well. After that it was really obvious what was going on. Hopefully now the members will settle down a bit, because many got upset.