two people are shown a website in a frame below an input field. they both must type in keywords to describe the page. if both keywords matches, it proves that both people work for the same SEO company and they want to stuff more keywords to their URLs :-) - pontifex
Exellent suggestion on how to game it. People in India, Russia and the U.S. mid-west must be BS. Google figured out how to get quality control and data entry done for less than anybody would do it, (for free).
Unfortunately, people will play the game, and eventually only images that meet this 50/50 id test and have matching surrounding page content and/or alt tags will rank well.
I wonder if "get people to work for free" fits with the "Do no evil" mantra?