We entered the blog market at Christmas, one thing that they are great for is filling content on member-sides of sites. Great updated content, of course, only if you have people updating them, which does cost a bit. The two we launched are:
CelebNewsWire - The Celeb News and Rumors Blog
and
SexWrecks - A Journal of Crotch-Borne Mockery. And Ruin.
We also put out RSS feeds on both so others can use them to update their sites.