Hitwise Presidential Candidate Demographic Data

Hitwise offers demographic data as an option with their web data service. One of their analysts offered this look at traffic to McCain's, Clinton's, and Obama's websites, based on bucketed demographic persona types. Overlaying the data allows for great a comparative look at the candidates breadth and level of appeal.

The short of it is that McCain appears to appeal to a broader population segment than Hillary and a far broader than Obama.