The owner of the FFA site sends a "confirmation" (advertising) e-mail to the contact address every time a web site is submitted for listing. Every FFA page owner does this every time.
There are a zillion FFA sites out there. There is even software available (FFA Blaster) that will submit your web site link to thousands of FFA pages at once.
There are also "Link Advertising" sites that offer to submit your web site to "a thousand search engines" so that you can start getting more traffic to your site. What they mean is that they will submit your site to Yahoo, AltaVista, and 998 FFA pages.
The novice takes them up on their offer and gets 998 "confirmation" messages from the FFA owners. The experienced user knows about the "confirmation" e-mails so he uses a bogus address, or your address, so he won't get the traffic.
The real purpose of having an FFA site is so the owner can collect addresses to send his advertising mail to.
One FFA page owner I corresponded with told me he got hundreds of new submissions every day, and the response from his "confirmation" messages was making him a tidy profit.