[patio11]

What are they doing?

Ad sales. It isn't a very headcount-efficient endeavor once you get past self-served options. A lot of the big corporate branding accounts who have huge amounts of money to burn and don't track conversions (I believe in poker these are referred to as "fish") require someone to chat up the media buyer for a while.

Branding campaigns are only a backup strategy, mind you, in case that Digg doesn't sell out their inventory of inflated page views by rabidly anti-commercial poor adolescents. For some unfathomable reason.