Blog and wiki authors are now inventing a new era of media, and it is my belief that this new media is going to invent a new era of politics. If broadcast media brought us broadcast politics, then participatory media will bring us participatory politics.
To add on to Web 2.0 observations...
With regards to Wikipedia, Emigh & Herring argued in 2005 that "a few active users, when acting in concert with established norms within an open editing system, can achieve ultimate control over the content produced within the system, literally erasing diversity, controversy, and inconsistency, and homogenizing contributors' voices."
In the same vein, somone has finally found out that the top 100 Digg users control 56% of Digg's homepage content. Looking at the latest Ajax Aiki startup, called Wetpaint, its easy to notice that there are always a few people who are doing the work. In addition, look at 43things, and you will realise that after so many months since it was founded, the number of users seem to be stuck at below 500,000 - rather, the nummber of users have more or less reached a plateau.