clipped from: tpmelectioncentral.talkingpointsmemo.com The ad seems to be formulated to deal with a critique of Obama that has surfaced in the last few contests: That in the wake of the "small town" comments, he has trouble relating to or connecting with rural voters.
Interestingly, Ben Smith notes that the Obama camp hasn't blasted this ad to reporters in the way they usually do -- perhaps because liquid coal technologies aren't particularly popular with environmental activists.