Some of these numbers have been reported already on MyDD. I would disagree slightly with Jerome's post that the Obama campaign has discovered "well-to-do students with disposable income." It's not that they are making large donations, it's that they are making them in incredible numbers:
Students were able to buy tickets for the Boston event at a discounted minimum price of only $23 and yet managed to raise $100,000. That means students purchased thousands of tickets. The Harvard Crimson reported that over 175 Harvard Dems attended the event. As Jerome noted:

For the Boston event, there's 250 tickets sold by Mitch Robinson, a Tufts senior, "distributing them outside the library and in the dining hall", another Obama supporter "sold 118 tickets to her BU peers", and you get the idea.

The success of the UIllinois at Urbana-Champagne SFBO chapter and Million Strong for Barack show however that this success isn't just limited to the huge small-donor "concerts" that Obama has been holding but that there are a number of great grassroots efforts spawned by students at college chapters all around the country.

Youth Vote Narrative:

Mike Connery has put up a number of thoughtful posts on MyDD about his worries that an Obama loss could lead to a media narrative that young people failed to turn out and have an impact --- that youth vote organizers might be risking too much by putting all of their eggs in the Obama basket.
While this fear may or may not be well-founded, Obama remains a remarkable opportunity to engage young people for the first time in politics --- to make their first contribution, to walk their first precinct. These positive experiences have got to translate into greater involvement in the future, regardless of the general election candidate. Young people are learning what they can accomplish collectively.
As many have noted, this strategy is reflective of Obama's background in community organizing and organizations like ACORN that solicit minor donations from even their low-income members as a way getting them engaged and building a movement --- and these young people aren't showing up to hear U2, they're showing up to hear a politician give a speech about progressive politics.
Adam B posted a great quote from David Sirota in a comment to Jerome's post:

[T]here is another model that very few people talk about - the one where lots of working people give lots of small dollar contributions. People like Vermont Sen. Bernie Sanders (I) have been doing this for years. Howard Dean did it in his presidential primary run. It's a much harder path, of course, because it's much harder to organize lots of people than it is to organize a few wealthy fat cats. But in the absence of public financing of elections, campaigns that try to rely on lots of little contributions are the next closest thing to a small-d democratic election system....
Groups like Moveon.org are flipping [the] smoky backroom model on its head, gathering a very large group of contributors who each give just a little bit. Such a model doesn't require regular folks to cough up hundreds of dollars. On the contrary, if millions of people kicked in $5 or $10 we might have a whole different country.
Getting more people to contribute small sums of money to political causes will require a change in mindset. As political fundraiser Chris Gruwell says, we need to look at political giving in the same way we look at the basket that comes around at our place of worship. We chip in what we can, no matter how modest, because we believe in the charity work that our money funds. That is the way we need to think about supporting good people running for office, because government can have as big if not bigger effects on society than almost any other institution.

Despite the great work that youth organizations have done registering new voters, I would argue that in the end, historically, the greatest impact has come from the wave generated by the arrival of a leader able to speak to young people and articulate a call to public service --- the way JFK motivated a youthful Chris Dodd to join the Peace Corps --- and that the best thing we can do is recognize these waves when they come and ride them as best we can.

Camp Obama:

Dan Rather just did a great special on HDNet about Camp Obama --- an effort in Chicago to train mostly young people to work for the campaign in the early primary states. The segment includes a group interview with Mary Hodge, Deputy Youth Vote Director, Jocelyn Woodards, who's the director of Camp Obama, Sean Eldridge and Tobin Van Ostern of SFBO. Mary Hodge in particular notes that Obama's campaign has been the first she's worked for to fully-fund the youth vote campaign and do more than just "bring in volunteers and stuff envelopes."

The most unique thing about this campaign is that we are actually fully-funded. The campaign manager knows we exist. We're not just seen by the campaign as the red-headed step-children, if you will --- that we just provide volunteers and that's it. And it's just so unique, because they really take us seriously. Every campaign I've ever been on, they say they take us seriously, but really they just take us seriously that they want us to bring volunteers in and stuff envelopes... This group... We are targeting different college campuses, we are building lists, we are expecting these students to come out and vote for us.

Camp Obama has already had over 2,000 people sign up for the trainings throughout this summer in Chicago. Rumor has it that they are going to be taking Camp Obama on the road in the fall. Boston or Los Angeles with their college-rich populations would probably be ripe targets.
In this election cycle, we need to choose the most effective spokesperson for progressive politics for the next decade and the candidate most likely to have a transformational impact on American politics --- the candidate with the most potential to bring new voices to the table and expand the Democratic base. Obama is shaping up to be that candidate.

(Obama supporters should get the RSS feed for the SFBO blog and read up, they do good work --- I'm in no way affiliated, just a fan.)

Owning a part of the campaign:

Just as a final note, Ezra Klein over at the American Prospect's TAPPED discussed Obama's number of donors, quoting a very cynical Chris Hayes:

the psychology and motivations for small donors is quite different than for large donors. If you're a big donor, you want access: a rubber chicken dinner, a photo-op, maybe a phone call answered. For small donors, it's entirely a different calculation. It's not because you think the $50 will buy you influence, or even, really, make that big of a difference. It's an identity statement, and a desire to be a part of something. When you pay that money, you become part of the Obama Phenomenon. That's what people are buying.

Although there is some truth to this (and talking about the community organizing strategy is a much better way of describing it), I think the first poster named Wendell has the right response by taking on the implication that Obama's celebrity is selling the tickets and not his message:

Hayes is way more cynical than your squib let on: "Those of us who shelled out the money, likewise were purchasing some small part of the hype and fame--some minor morsel of celebrity for ourselves."
As one of the quarter-million Obama contributors, I say: BS! If I want some small part of the hype and fame, I'll buy Paris Hilton's perfume. If I want a Democratic Party nominee who doesn't have 60% of independents who, right now, say they would never vote for that candidate, and who isn't a trial lawyer to his core (many other lawyers are allergic to that type), then I want Obama to win, and, obviously, contributing helps (mother's milk and all)--assuming that his campaign can spend contributions effectively. That sort of calculation, I would submit, has very little to do with buying into my very own little piece of a celebrity's culture.