I first read Ender's Game about 10 years ago, and although I enjoyed the main plotline the most fascinating (and unbelievable) characters were Demosthenes and Locke -- who were essentially proto-bloggers, ante litteram. These were actually screennames used by Ender's siblings as they debated pseudononymously through the internet and shaped world policy.
From 1994 to 2003 I thought such an idea was silly. I used Usenet and knew there were a lot of smart writers, but I also knew that no one read Usenet -- at least no one who mattered. As Sean notes, both he and I were behind the curve by that point, and are only now catching up.
I've written before that the American who will be elected President in 2028 almost certainly has a blog today, and that may be a conservative estimate. I've also written a lot on this blog that would probably make it very difficult for me to have a political career, but would it be hard for someone with an opaque, non-blogging history to run against me? No one can predict such things. Imagine being able to read through decades of writing by a presidential candidate, and imagine how much more difficult it would be for wafflers like John Kerry to get elected to any office.
Someday blogs may even replace the press conference. Why bother dealing with pesky reporters when you can just post to your blog and have everyone in America (who's interested) read whatever you have to say? I think blogs will eventually bring us much closer to our politicians, and make the interaction much less formal (and tedious).