Tag Your (Flickr) World

Is there anything Web 2.0 can't do? Earlier this week, the photo-sharing site Flickr rolled out a new feature called geotagging, letting users tag their photos with the location of where they were taken. This is done via a gorgeous AJAX-type interface that lets you grab sets of your photos and drag them onto a zoomable Yahoo map of the world, which automatically tags them with the exact location you drop them on.

And if that's not brilliant enough, the geotags have been folded seamlessly into Flickr's preexisting tag-based search. Want to see all the photos of graffiti in New York City? All the photos of sausage in Germany? All the photos of aurora borealis in North America? Just scroll the map to the part of the world you want to search, and type in a keyword. Done.

The applications of a huge community-based database of geotagged photos are virtually infinite. (Special emphasis on huge: Flickr has 228 million photos in its database with an additional million photos added daily, and 1.2 million photos were geotagged within the first 24 hours of the feature's launch—far exceeding Flickr's expectations.) Moving to a new neighborhood? Scout it out first on Flickr. Need a free illustrated travel guide to Romania? You got it. Plus, like, a million other uses that neither I nor anyone else has thought of...yet. Seriously, mind-boggling stuff. —John Mahoney