The first presidential debate was streamed live, which just shows you that the Internet is becoming a mainstream news and entertainment outlet. YouTube has channels for both candidates. Both parties are working the websites, forums, "social networks", etc. to get the message out and spread the word.
All of this to hit the Undecideds, because the people that HAVE decided who to vote for will not be changing their minds. All persuasion is targeted at the Undecided.
Following the first debate, T. Boone Pickens was having a web event about his Energy Plan for America. The PickensPlan website was clogged 15 minutes after the debate ended. Are people engaged about the issues facing America right now?
I think in 4 years the Internet will be even more important for politicians. I caveat that with the fact that metered broadband may affect that since people won't be streaming video if they have to pay for it. They'll watch TV.