I see three groups:
1. Hillary supporters (I was in this group) that immediately went to Obama in March or so after it became clear what was going to happen. Have no problem with Barack, are enthusiastic about Barack, etc.
2. Hillary supporters that held on to the bitter end. Might not have jumped over right away, but are either coming about right now or have come about. Are rational and therefore listening to Bill and Hillary.
3. Irrationals. Will not support Barack even at the behest of Bill and Hillary.
This move is clearly targeting group 3. If, at this point, these people ABSOLUTELY POSITIVELY will not vote for Barack Obama, then nothing he could have done is going to change their minds. Nothing. Probably not even putting Hillary on the ticket.
Hillaryis44 and Hillaryforums are both very much in love with the Palin pick. The question is how many people do Hillaryis44 and Hillaryforums actually represent, and, as a side question, where are they and do they matter?
I've found that we're talking about an incredibly small but loud group of people. I just don't think this is going to be a wise pick over the long haul. Salient issues are going to come up that Palin won't be able to answer for (and shouldn't have to-- she's not Hillary Clinton and doesn't share any of her principles) and will lose support of all but the most crazy 3s.
If you supported Hillary Clinton because of what she stood for (and not just what she was) and you do not support Barack Obama (or some even more liberal candidate...lulz), you are irrational. I said the same thing when PoliGAFfers in January said, "IF HILLARY WINS I AM SUPPORTING MCCAIN!!!!" Fine, then you are not voting in your own interests.
There's no point in attracting 3s. They are crazy.
edit: How many lines is that, Charlie?