Giving away t-shirts to the latest over $25 donors.
Very smart move. The Obama campaign depends on repeat small donors. Now for a donation donors recieve something that publicizes the campaign and the Obama team adds to their database for futher appeals. The people who donate also want the t-shirt. The grass roots Obama campaign is usually out of the normal campaign items that supporters want - buttons, signs, t-shirts, bumperstickers. Can't keep up with demand.