It's impossible to know of course (I'd love to see some sort of poll of the audience), but I really think the Clinton campaign is misreading the standing ovation at the debate. Among other things, there was obviously a large pro-Obama crowd, given the booing for Clinton's "Xerox" comment and the applause for Obama at many points. Yet as far as I can tell, everyone was standing and applauding at the end. Why would these Obama supporters be applauding? It really seems to me like there was a response to the valedictory/ concession aspect of it, even if that's not what Hillary intended. That she was "honored, absolutely honored" to be on stage with him, and that "no matter what happens, we're going to be fine." And I'm not the only one who took it that way, to the point where she had to give an official denial on Friday that those words amounted to a concession.
At any rate, the Clinton campaign is taking sections out of that last part of the debate for a campaign ad because they seem to think that those are the sections that got the big response. More details (about the ad and background) here:
http://thecaucus.blogs.nytimes.com/2008/02/23/the-moment-interrupted/#more-4334