Found TinEye the other day for reverse image searching, basically you can stick in an image or a logo and it will check it’s database to see if it can work out if any look similar or the same as the image you put in. Pretty handy for doing a basic search to see if a new logo is original or a copy of something else. However it’s still in beta and only has a fraction of images online so it’s far from perfect. I fully expect Google or Bing to snap this up or copy the idea at some point down the line.