I think they don't mind filling up their database with free listings first as a directory is useless without any listings. Who would pay for a listing if there are no other listings in the category or directory itself, this would tell people must be useless if nobody else is in there!
I've known about this for a couple of years and have gotten a few sites listed this way. I am a little unsure about doing it now for some sites as se's are moving more and more to a regional specific results genre and am afraid if I list a site say in uk dir that a site would rank well in uk search but not in general search. Any feedback on this theory?
Thanks for the post, great read People are asking for $50 / year to include my sites Now I know how they do it