A website im on, (full or brainy ladys) had a member sign up, with advertising in the signature, and made what seems to be normal posts. However theres a sinister side to this and one of the ladys on the site found out what it is, so i thought i would link you all to the website of the person so you can see what they are doing. They signed up under their name of PRbot.com
http://www.webworkshop.net/seoforum/...3364&highlight