Is there any way to shut down mass mailers?

Tried many tricks to prevent this siphoner

[creepychris]

Part I) A competitor website continually siphons my sites. I have tried and at times have succeeded to shut him down using both .htacess and a robot trap. But each time I succeed in shutting him down he circumvents it. He circumvents it by changing IP (using internet cafes which limits IP bans) and changing user agents (which limits banning by user agent) and i guess he has circumvented the robot trap because I find out that after one of his flyby's the trap has not been requested (Although depending on advise from this thread, I may try to build a better robot trap).

Part II) He then takes this info and mass e-mails using a variety of yahoo.com, hotmail.com, and netscape.com.

My questions is: If he is this slick, is it even worth trying to prevent him? Or should I just let him have his way and get on with my life?

I have recently tried to e-mail abuse at the various networks but somehow I don't think that will have much effect.

[drbrain]

You've tried being defensive, but it hasn't worked.

You need to go on the offense!

Cause him pain of the legal kind.

[creepychris]

I wish legal action were an option but that is the beauty of what he does. There is no trace to him:

He siphons from an internet cafe so the IPs that I get are useless and then the e-mails (which all have links back to his site) are written from hotmail,yahoo, and netscape accounts, which I am assuming he has gotten without divulging his real information. So although all of the e-mail spam he sends goes back to his sight he can just say 'prove I sent it' or 'somebody is framing me'.

[roitracker]

Do a whois lookup on the domain & send a "cease & desist" letter from your lawyer to both him & the hosting provider. If he's mass mailing, there's always a trace, so lookup ownership of the IP that's sending the emails too.