Facebook, right in the header.
Google AdWords -- in the Campaign Management dashboard.
MySpace, between pages. This is actually an interstitial ad for E-Research Council, but still.
Meanwhile, traditional media entities like PBS have partnered with Google to make this year's election the most transparent ever. Got a mobile cam? Covertly video your experience at the ballots. Twitter and My Fair Election are also using crowdsourcing to police the polls this year.
Other sites jumped the gun: betting destinations cast lots for Obama, and even Facebook Lexicon "suggests" (eh, I'm iffy about this) an Obama win.
We'll know in 12 hours.