I learned the other day from a friend that taggers—the spray paint kind, not the online variety—are often quite predictable. If you look at a map of the locations where they tag, you’ll often found a common radial pattern of increasing density of their tags. The closer to the center of that circle is the general vicinity or even the very house that the tagger lives in.
Applying some social computing to the idea, I could see a useful mass collaboration social experience, where the task is to allow anyone to submit smartphone photos with GPS locations of where they see a tag. You can then plot this on a geo-map and over time create a result of frequency of occurrence. Social sites like Brightkite and Foursquare that let you share your location prove that it’s quite possible to create such a map.
So, there’s a possible project that can apply to any location
really, with the help of any willing citizens. There are some practical issues:
identifying the actual tag signs from different taggers, collecting enough data
for useful information, and cooperating with the police to utilize this
information. However, these are not insurmountable and it would help the community