WWW Robots (also called wanderers or spiders) are programs that traverse pages in the Web by recursively retrieving linked pages. When a spammer's robot visits your website, blog, discussion forum, etc, they will check all the pages that you link to for email addresses.
Now you can fight back against their robots!
All you have to do is link to this page so that whenever a spammer's robot scans your page, they will be sucked into this one.
E-mail collecting robots will be sent in an infinite loop and will get dynamically generated fake e-mail addresses, adding enormous quantities of bogus data to the databases of the spammers, thus polluting those files so badly that they become essentially useless. They will have to clean out their databases or will receive a LOT of returned email :-)