Yesterday, the FlickrBlog mentioned a new web app that pinpoints properly tagged photos on Google Maps. A few Chicagoans have quickly gotten in on the act, as Downtown is already very well represented. You simply click on one of the markers, the map recenters, and you see a linked description and thumbnail. The GMaps features we know and love function as usual, so you can also zoom in or switch views. The satellite images provide an interesting contrast to the photos, especially in the cases of Millennium Park and other spots that have since been developed. To join the fun, geocoder.us provides a handy way to find coordinates for your pictures. And, if you're looking for another way to put Google Maps to use, check out this mash-up with Yahoo!'s traffic reports.