I've heard of a few friends of mine that have mentioned it...but I've heard conflicting reports of if it makes good money. I'm not quite sure how exactly it works, if its popups or what...but it might be worth a shot to try it...after all, you could just stop using it if it's bad...right?
Placing your classified ezine advertising is very similar to offline advertising. Think in terms of "The New York Times, or your own local paper, but with a much larger audience. It's your website or program ad appearing world-wide in a variety of online "e-magazines" or newsletters.