Over at Total Social Media, and as part of their Web 3.0 Lab, they've developed a pretty cool mashup of location and social/semantic data called Clima.me. Clima.me is a tool that measures the density of location-tagged data from a number of web apps (Twitter, Wikipedia, Flickr, Yelp, and Foursquare) and kicks back a Web 3.0 temperature for your location or, for that matter, any location on earth.
The interface is a bit spartan, but works because it doesn't get in the way of the data. It is comprised of a Google map of the location being measured, a readout of the individual scores for each web app, and a thermometer as a way to display the Web 3.0 "hotness" of the location being measured. Go ahead and give it a shot. You'll be surprised how much you like finding out how much Tweeting they're doing in Paris, France vs. Paris, IL.
In future versions, it would be great to see (or, at least have a path to) the underlying content. Another great visualization would be a Web 3.0 "heat map," to see the Web 3.0 climate presented like temperature data. I know they're working on improvements and I'm excited to see what they do next.
Try it now at http://clima.me.