The Pew Research Center conducted an online survey of 11,568 Deaniacs and has the highlights in "The Dean Activists: Their Profile and Prospects":

...Dean activists are far wealthier, better educated, more secular and much less ethnically diverse than other Democrats. A disproportionate number of Dean activists are white, well-educated Baby Boomers - fully a third are college graduates between the ages of 45 and 64, compared with just 9% of Democrats in the general public...

...Roughly eight-in-ten Dean activists (82%) describe themselves as liberal, compared with 41% of the convention delegates and 27% of national Democrats...

...most believe George Soros and other wealthy liberal philanthropists helped the party and progressive causes in general...

...They also support gay marriage by more than ten-to-one (91%-8%); half of national Democrats (50%) oppose gay marriage...

...More than three-quarters of Dean activists (78%) say U.S. foreign policy should strongly take into account allied interests. A plurality of Democrats (49%) agree, with 38% backing a policy based mostly on U.S. national interests...