Instagram: Kevin Systrom and Mike Krieger

In an increasingly app-focused world, you would be hard-pressed to find a user who hasn't encountered the massively popular photo-sharing app Instagram. With over 150 million active monthly users, Instagram's wild success is well known, but unlike other stories of tech triumph, few know the details behind the achievements of Instagram cofounders Kevin Systrom and Mike Krieger. With their experience from other companies, including Google and Microsoft, this pair gave new life to amateur phot...