> My understanding is that the purpose of tarpits is to cause spammers to > use up a critical resource - namely bandwidth. However, from where I > stand, they don't appear to do that.
As i see it, we're not directly causing the spammer pain -- most spammers don't connect directly to the final recipient's mail server. They connect to an open relay, tell it to send a message to a zillion people, and leave it up to the relay to deliver all the mail. Open relays are usually run either by people who don't know they're helping spammers or they don't care. But when their mail server starts crashing because there's no disk space left or it slows to a crawl because there are no file handles left, they'll either take notice and close their open relay, or their machine will be so slow it won't really be able to spam much.
