Microsoft is following up its enormously popular website that guesses your age with another new tool it's calling Twins or Not. It's pretty simple: you upload two photos, and Microsoft's machine learning will judge how similar the people in both shots look. It then chooses a final score ranging from 0 to 100. According to Microsoft's Mat Velloso, Twins Or Not took a total of four hours to create using a combination of Microsoft's APIs and the company's Azure cloud platform. Will it have the same viral appeal as how-old.net? Microsoft says its earlier project, meant to be another fun showcase for its machine learning, was used by "millions" of people, and our Facebook timelines would agree. Here again, Microsoft says it's not holding onto your photos after the tool runs its magic.