I came across this interesting entry on the Mobile Technology Weblog about linking wikipedia, the online encyclopedia created by volunteers using wiki software to locations:
"One of the most exciting things that’s going to happen in the next 10 years, in my view, is that the Wikipedia will move into the physical world. It may not be a Wikipedia initiative (ie it might be a new and different organisation that makes it happen), but the principles will transfer and apply… You’re in London and are standing in a pleasant, sunny street in Camden Town. City life is going on around you and you fancy the idea of knowing a little more about where you are right now… Using your phone, as if it was a PC mouse, you uncover snippets of information from the world around you. You click on an old house in the road and a wealth of digital information comes onto your phone screen. Some contain video and audio links." (whole article)