RG,
A tactic I have sen a lot on a couple other boards is the "New Member" posts a thread like this...
"Hi gang! I am thinking of getting (this product). Has anyone here used it and how good is it?
WWW.spamlink.com "
They then add a duplicate post on each subforum until a member or moderator sees the pattern and flags it as SPAM. SPAM of any kind is such a cheap advertising medium that you only need to make something like one sale per million messages to make a profit.