Google maps, based on technolgy from Keyhole, are fun!
There's a sightseeing group, Google Sightseeing,
and there's even a site powered by Powered by craigslist
and Google Maps. What Microsoft and Yahoo are up to?
Flickr, Flickr, Flickr, where art thou tags going?
For this and more see an MS guy's blog, "Map Wars heat up."