Why's it good news?
First, Ifill understands that her every movement, word, statement and attitude is going to be subjected to even closer scrutiny than might otherwise have been the case. Oddly, she will actually have to be more even-handed because she knows that everyone understands where her bias lies.
Second, this is a high-profile example of the systemic pro-Obama bias in the MSM. It allows those who otherwise might not have been aware of the Barack-worship in the press to hear about it in a way that drives the point home.
The absence or presence of a pro-Obama book changes nothing about the way Gwen Ifill feels personally (and I suspect that her feelings are shared by over 90% of the MSM). At least it makes it plain for one and all where her allegiances lie, and that kind of clarity is good.
But it does say something about either Ifill's integrity or her judgment that she saw no reason to mention this to the McCain campaign.