Microsoft's how-old.net isn't the most reliable age detecting software. The company set it up as a demo site and never expected it to go viral (two million shares on Facebook). While thousands of users checked in to see how old an algorithm thinks they are, Toronto's Covenant House used the social tool as a catalyst for a pressing cause. They created a web ad that shows Cale, a 22-year-old homeless man, stamped as a 43-year-old on how-old.net. "The message was simple: living on the streets robs kids of their youth," Josie do Rego, Director of Development and Communications, told Engadget. "We wanted to remind people that the streets are no place for young people."