Everybody remembers how Tom Sawyer converted the most dreaded task of painting the fence into an activity which his friends paid to be part of. Well our own little adventurous Google is doing just the same.
It has a mammoth task of tagging all the billions of photos it has into a searchable database. To save cost, resources and bandwidth it converted it into a game. You and a random partner will be shown a photo for 90 seconds and you suggest as many tags and titles as you can. Each matched title is considered good and 100 points are awarded.