Eric Fischer's "Locals and Tourists" Flickr set uses geotags to compare photos taken by locals (people whose photos come from the same city, over long terms) and tourists (people whose photos come from a city for less than a month, and who have some other city they usually post from) and produces colored maps showing the difference. Readers use Flickr's annotator to add explanatory notes. Here's London.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.