I am more and more impressed by Wikipedia. I think it is a mind-blowing example of technological watershed. Technology enhancing and magnifying a natural human tendency and bringing a new type of entity into existence.
Once the technology interfaces just right with how people work, with what people want to do, then BAM it takes off. In processing terms, wikipedia and blogs are insanely complex systems, which literally incorporate social animals - us - as filtering devices. Incredible. Think of the potential processing power you've got there, some of it just hanging about to be used once every few years, some of it beavering away daily, some of it collecting data in - you know - real life.
The success of wikipedia is also a counter-exampe to the tragedy of the commons. This is a dilemma of Game Theory, that common resources will be under-stocked and over-exploited. Wikipedia demonstrates that people can sustain a communal resource non-coercively, but only (I suspect) in limited circumstances. With wikipedia one has just, fortuitusly, hit such circumstances.
I suppose it will jump the shark one day. Or, alternatively, it will have massive currently unforseen real-life effects.