just read through this topic and thought i'd add some insight. i've dealt with this issue on my forum numerous times. the problem is that this guy is probably not a real person, but rather a bot.
a bot is a computer that generates fake e-mail accounts and sets itself up on web sites and forums for advertising.
and the hardest part of this is the bots use multiple ip addresses, so banning them is sometimes useless.
and replying or sending them e-mail is a waste of time because the e-mails usually just get deleted off the server they are sent to.
so what can you do?
as an admin, you can set the forum up with e-mail verification, or an encrypted code that needs to be manually typed in by a real person upon sign up to verify that it is not a spammer. admin can/should be able to disable html code if the spammer is posting links or setting up backgrounds in the forum.
every member has an ip address. admins can take the ip address and check it out on the arin (american registry of internet numbers) to see who this spammers isp is. once looked up, there will be an abuse e-mail address or phone number that can be used to report this person. after so many complaints are filed, the spammers isp will usually pull the plug on that persons internet service entirely.
hope this info helps. been there, done it.