Here's a fascinating tool from our world-wide overseers at Google. www.Sightsmap.com is a graphic representation of all the photos taken in the world and uploaded to the Google photo sharing site Panoramio.
How cool to see where in the world the most photos are taken! Now, these are only the photos uploaded to Google, but still it's an interesting representation of all the photos taken. You can also zoom in on specific areas, like New York City; this is where I think Sightsmap might be a useful tool and not just an interesting time waster.
You can zoom tighter, all the way down to specific areas and even see some of the photos that have been taken. The ability to zoom in and explore may be helpful to travel photographers looking for ideas of what to shoot when visiting new places. Doing research about your travel destination in advance will help you get better shots while traveling.