Via the Chicago Sun-Times, a Zogby poll* suggests that Oprah Winfrey may have done Obama little good--and perhaps even harmed him--among women voters in New Hampshire. I do think the Oprah tour risked highlighting the sense some people have that Obama is more a media sensation than a serious political leader. That said, the tour garnered Obama a ton of soft media coverage and produced a sense of momentum and success at a critical moment. Moreover, a major element of the three Oprah events was getting attendees to sign pro-Obama "pledges" and collecting precious contact information like email addresses.
Update/credit where due: That Zogby poll was commissioned by the Lifetime network. Here's the whole thing, which I now see also includes the interesting fact that 40 percent of New Hampshire women remain undecided.