Never mind that President Obama left California today with millions of dollars in fresh campaign cash gathered from hundreds of his wealthiest donors.

Obama says what sets his campaign apart from any other is that “we rely on ordinary Americans giving what they can – one grassroots donation at a time.”

“I enjoy talking about fundraising deadlines as much as I imagine you enjoy hearing about them,” he said in an email to supporters. “But this Friday’s deadline is important. It’s a chance for us to prove how we’re different from any campaign in politics.”

The message is geared towards pressuring small-dollar donors to open their wallets before the end of the second major fundraising period on Sept. 30.

Obama has offered to place a personal phone call to a select group of supporters who give as $3.  His campaign is also running a sweepstakes for grassroots supporters to win dinner with the president.

Organizers have also pushed a grassroots fundraising challenge through the campaign’s website with a goal of garnering 20,000 donations by the end of the month.  As of this morning, 8,789 had participated, according to a posting on the site.

Obama famously engaged record numbers of small-dollar donors in the 2008 campaign, and is well on the way to topping one million contributors for 2012.

Still, as a percentage of overall campaign funds, Obama has relied heavily on wealthier donors.  In 2008, the Obama campaign raised 76 percent of its total funds from donors of who gave $201 or more in total.