You know, this story kinda tweaks me a bit. I don't want to belittle the contributions of folks like Steve Rubel at CooperKatz or Ketchum's new effort in the "personalized media" space, but since when do advertising agencies need to start specialized divisions to adequately leverage blogs and community sites? There's already a department at ad agencies that can deal with this - it's called the online marketing department.
The blog networks have agency-represented advertisers. Some agencies (like mine, for instance) are going directly to blog publishers to cut deals. It doesn't require a specialized division, and I think Mediapost's implication that it does is kind of silly.