Their apps and websites are familiar, and millions of us use them every single day – but how many of us really know anything about the entrepreneurs behind some of our favourite phone apps and websites? The massive popularity of their apps has taken the innovators by surprise, too. Kevin Systrom & Mike Krieger Kevin Systrom studied at Stanford University and went on to do an internship at Odeo, the company Twitter originated from. After two years with Google, he  met  Mike Krieger, a Brazilian entrepreneur and software engineer, and in 2010 the pair went on to found Instagram, the photo sharing app for mobile phones that allows users to take pictures on their smartphones, customise them and share them on the app or via Twitter and Facebook.…