We can use all sorts of methods for search. The latest I think is a bit out there is Retrievr from System One.
They give you a little drawing pad and the search engine goes out and looks for shapes in images that match what you drew.... now that gets a little scarry... and a bunch of fun... soon people can play 'Hide and Seek' or Pictionary online. Take a picture or make a drawing, post it online and then have your friends draw a part of it and see who can find the page it is on first!!!!
Let the fun begin.