I like The Search Engine Election: 2008 Presidential Campaign Scorecard Jonathan Mendez put together as it gives me ideas of how you measure effective of a paid campaign for a political candidate:

2008 Presidential Election SEM Performance Scorecard

While it's clear, according to the scorecard above, that Mitt Romney wins, most of the steps would be very easy for any candidate to immediately put into action with slight modifications to their paid campaigns.

But the other point is more troubling and though provoking:

"…If candidates are not even doing the SEM basics yet how can we expect they will leverage the more targeted opportunities to connect with voters through interest, behavioral and content targeting and testing technology. Only Romney had targeted landing pages and most every site I looked at was woefully poor in conversion optimization. Others agree. With online contributions 15-30% of total fundraising what candidate wouldn’t want even a 10% bump in donations through some site targeting and testing?"

It's funny how putting information in a scorecard format focuses interest and questions (and the scorecard suggests, by it's format, solutions).  I would expect that some of the candidates will put more focus in the targeting and testing technology soon enough. 

My guess is most are "testing the waters" and, honestly, most candidates probably don't have people setting up the targeting and testing, yet, that he mentions in his post….but it sounds like they all should.