obama incorporated:
Since announcing his candidacy in early February, Obama has raised millions of dollars from corporate fat-cats and multinational corporations. While the young candidate has leaned heavily on law firms to which he has professional connections - he's also not been afraid to dip in to the trough of Big Business. And it's a sure sign Obama is a real contender for his party's nomination.
(...) When Howard Dean's campaign began to gain momentum during the 2004 elections, the former Vermont governor had not flipped through his party's corporate black book, and instead relied heavily on the grassroots to provide fuel for his presidential bid. The party's elite, nervous and unsure that Dean could be one of them, taught the naïve doctor a harsh lesson: the establishment quietly sacked Dean for America because he had not accepted the way business is done in Washington.
(...) There's no question that industry loves Barack. As of March 31, UBS, the second largest bank in Europe, has given over $165,000 to his campaign. The Exelon corporation, which is the nation's largest nuclear plant operator, has donated almost $160,000. The investment Goliath, Goldman Sachs, has also fattened the pockets of Barack Inc. with over $143,000. Citigroup has given well over $50,000 with Morgan Stanley close behind at $40,000. Wall Street has Obama's back.
(...) The Obama campaign insists the funds he is raising won't influence his positions on any matter, politically or otherwise. They assure us Barack is untouchable. But whom are they trying to kid? Frankly, big donors aren't accustomed to handing out hundreds of thousands of dollars without any kickbacks. They don't write checks out of good will, they do it because they in turn profit. As Ken Silverstein wrote in an online article for Harper's:

To anyone who thinks Obama is blissfully oblivious to the fundraising imperative, consider the following: in one of his earliest votes as a senator, Obama helped pass a class-action "reform" bill that was a long-standing and cherished goal of business groups. (The bill was the focus of a significant lobbying effort by financial firms, who constitute Obama's second-biggest single bloc of donors.) Thanks in no part to Exelon I'm sure; Obama has championed nuclear power as a "green" technology. Through his elaborate fundraising channels Obama has also formed a close relationship with Skadden, Arps, one of the largest corporate law firms in the country and one of the largest contributors to the Democratic Party. Skadden, Arps was the legal team hired by David Jones to help derail Howard Dean. Consequentially they were also a top contributor to Kerry's campaign in 2004.