Page Hunt is a game developed by Bing for investigating human research behavior.
It is a so-called "game with a purpose", as it pursues additional goals: not only to provide entertainment but also to harness human computation for some specific research task.
The term "games with a purpose" was coined by Luis von Ahn, inventor of CAPTCHA, co-organizer of the reCAPTCHA project, and inventor of a famous ESP game.
Shown a webpage, the player must find the best keyword or keywords which would bring this page to the list of top 5 search results by Bing.
The higher the rank of the page within the first 5 results, the more points the player gets.