What sort of surprises me about Obama's mega-take is how disconnected it is from his apparent momentum. He appears to have functionally matched Hillary's fundraising, despite routinely trailing her in national polls. Moreover, he's not only been unable to gain much early traction in Iowa, where Edwards leads, but he just ceded second place in New Hampshire to Edwards (with Hillary in first).
We may be seeing the further disassociation of fundraising from widespread support. Take Obama's haul. Given the remarkable 100,000 donors, I'd guess you're seeing widespread support from the "netroots," broadly defined. In other words, from computer literate, highly-informed, well-educated, fairly young, political junkies who, due to the sophistication of online fundraising techniques and their particularly high response rate to such appeals, are emerging as an actual funding bloc even as they remain weak as a voting bloc. That said, most primary voters, as we saw with Dean, are not computer literate, highly-informed, well-educated, fairly young, political junkies. We'll see whether Obama could build the bridge that Dean could not. Clinton, meanwhile, has the broadest support but not the broadest donor base, because he supporters skew older, poorer, and are less politically involved.
On the other side of the aisle, it looks like Romney's huge haul relied heavily on donations from the Mormon community, which presents an even more extreme version of this problem. Most primary voters really aren't Mormons, and it's an open question whether they're comfortable with a candidate funded heavily by that demographic. In his case, the money may actually turn into a liability