The Clinton campaign says it raised $2.5 million online last night in the three hours after the Pennsylvania primary was called, and 80% of that came from new donors. Clinton herself made clear mention of her campaign's url, HillaryClinton.com, during her victory speech, and if you look closely you'll notice that her campaign placards also reinforce that. Anyone clicking there was taken straight to a donation page, as Marc Ambinder pointed out last night, where the campaign is asking for as little as $5 from potential donors.

Clearly, small donations (those less than $200) are numerically dominating the Democratic contest and buoying both candidates. The nonpartisan Campaign Finance Institute reported yesterday that:

The three remaining candidates raised nearly $78 million in March, slightly more than the $77 million raised in March 2004. For the second month in a row, more than half of Senator Barack Obama's and Senator Hillary Clinton's primary contributions – 60% and 58% respectively – came in amounts of $200 or less. For both Democrats, about a fifth of their money came from $1,000 and over donations while another fifth came from $201-$999 ones. In contrast, Republican presumptive nominee Senator John McCain raised only 18% of his primary contributions from smaller donations and 10% from mid-sized ones. Fully 72% of his total individual contributions were in amounts of $1,000 and over, with 52% from maximum $2300 donations.

Through the end of March, Obama had raised far more in small donations than Clinton: $101 million to $44 million, respectively. The CFI does caution that "all of the above figures refer to donations, not donors. Statements from campaigns and preliminary CFI analysis of FEC data indicate that a substantial minority of small donors give enough times to reach aggregate contribution levels of more than $200."

What does all this mean? Three things: First, that a substantial number of Democratic voters have become very comfortable with giving to candidates online. Second, that there is probably enough grass-roots support for Hillary Clinton for her to keep financing her campaign into the future, though still little indication that she can reach parity with Obama. And third, that the Democrats have completely overtaken reversed the Republican party's historical advantage in the small donor fundraising arena, a shift that will be very significant for the general election.

UPDATE: The Washington Post reports that the Clinton campaign says it "has experienced a crush of new contributions overnight that now totals more than $10 million." If true (and god knows these reports of online contribution figures have become almost as slippery as the poll projections in New Hampshire), this amount should certainly keep Hillary in the race for several more weeks.