I first start of with PostFusion http://adminfusion.com you'll see the post fusion link up top. Its basically a post exchange, works wonders.
Then I start submitting to del.icio.us, stumble upon, and now http://forumfads.com (shameless plug). Then …
I think the only + sides would be that someone else can't register the other extensions and profit off your work. And if you develop a well known respected site and sell it off you can get some good extra money from those extensions
I dont understand why they pcik some sites and not others. Its on an editor to editor basis so theres realy no figuiring it out.
From what I've been hearing though, DMOZ is dead.