I still haven't watched it, but I have been following the blogospheric coverage, especially through www.fivethirtyeight.com. One thing that was being theorized coming into the debate was that the format, especially the lack of direct interaction, was going to favor Palin. Another was that Biden needed to be careful and not attack too much, not come across as being mean to her.
Is it possible that the format, by depriving Biden of the opportunity to interact directly, wound up helping him more than her? Not sure if it's possible to tell after the fact, but the coverage I am reading is indicating that he came off as more sympathetic and human than she did, in addition to being more qualified.
Then again, I'm not reading everything (unlike Governor Palin, who apparently reads "all of" the newspapers and magazines), so this may just be an artifact of small sample size.