An excerpt from David Shuster’s apology:

Last night I used a phrase, some slang about her efforts. I didn’t think that people would take it literally, but some people have, and to the extent that people feel I was being perjorative about the actions of Chelsea Clinton making these phone calls, to the extent that people feel I was being perjorative, I apologize for that. I should have seen people would see it that way. I’m sorry.

Shuster must have been using this definiton from UrbanDictionary.com:

2.) to pimp is to advertise (generally, in an enthusiastic sense) or to call attention in order to bring acclaim to something; to promote.