First Instagram photo: This adorable dog, July 2010
What is it with social photo-sharing sites and adorable pet pictures? Oh, wait, never mind, that's pretty obvious. In July of 2010, Instagram was an app called Codename and wasn't available to the public, but it did have this picture of a happy dog and somebody's foot. (The photo was uploaded by company founder Kevin Systrom, and we're going to guess that both belong to him.) By the time the company was ready to celebrate the second anniversary of this photo, it had already been bought by Facebook for $1 billion.