Columbia University alumni are responsible for many, many startups. And according to this Crunchbase article, the school ranked #6 on a list ranking "universities according to the number of alumni who founded startups that raised $1 million or more since last August." That's ahead of Carnegie Mellon, Penn, and Yale.
For this slideshow, we took a look at 15 tech companies started (at least in part) by Columbia alumni that found great success of their own.