[lukejduncan]

There is a gmail plugin for sending canned responses. For repeat spam offenders I create a filter that automatically deletes the email and responds with a canned "Stop spamming me. Your original email was deleted and never read." I never have to deal with the spam and they have to deal with mine.

[GoodIntentions]

That works great if the spammer hasn't forged the return address. Many spam emails contain forged headers and a working link to the scam website in the body.

A few years ago some #$^%er sent a few bazillion porn dvd spam emails with one of my domains in the header. An amazing number of admins/folks like yourself actually reply to a forged address.

[donatzsky]

That's assuming your replies end up in a mailbox they actually monitor, though.

[lukejduncan]

Typically these repeat spammers are individuals who manage some community email list (think apartment association or university student org) and don't know how to do anything but add people and copy/paste into the to field. For these people it works great.