Apparently Jason Calacanis, one of the early originators of the blogging medium, is jumping ship. He is done with the catty comments and slew of linkbait.
Still, according to this post in the courrier-journal, there are gleaming success stories. The Marriott group can trace how many reservations have been made through their blog (odd scenario).
If you are looking for examples of where corporate blogging can work, definitely check out this post on marketing in the blogosphere.