Strictly speaking, I suppose it has to do with press releases and such that companies make. But practically speaking, the real worth Colleen provides to YC is PR control, Colleen is an ex-TechCruncher (with the right tech news contacts, seems she's also worked at Financial Times and GigaOM, and more), she knows what to say and when how to say it.
An editorial director is a bit different from a corporate communications person. Many/most VC firms (indeed, many/most companies in general) are now looking to attract audiences of their own rather then rely on the eyeballs gathered around new sites.
That is an interesting possibility, I think yes, they will do that. It's like a more glorious version of pg's essays... except more strategically thought of (as you would expect from a large company).
Probably doesn't hurt to have a huge network of important contacts though :), the need arrives at unexpected times.
