I found this on Ian Irving’s blog, False Positives, and it’s such a great idea, I need to share it with you immediately!
It’s called Spam Poison, and here’s why you should think about incorporating it into your blog/site:
WWW Robots (also called wanderers, spiders, crawlers, or bots) are programs that crawl the Web continually retrieving linked pages. When a spammer’s bot visits your website, blog, forum, etc, all pages and sites linked to it will be searched looking for email addresses.
redirect email harvesting bots to trap sites that will feed it with an almost infinite loop of dynamically generated fake email addresses, mostly on known spammer owned domains! This will render their harvested lists pratically useless and of no commercial value.