[This is the second in a series of posts about Stack Overflow. The first one is The Stack Overflow Age .] Around 2010 the success of Stack Overflow had led us into some conversations with VCs, who wanted to invest. The firm that eventually invested in us, Union Square Ventures , told us that they were so excited by the power of gamification that they were only investing in companies that incorporated some kind of game play. For example, Foursquare. Remember Foursquare? It was all about making your normal post-NYU life of going to ramen noodle places and dive bars into a fun game that incidentally generated wads of data for marketers. Or Duolingo, which is a fun app with flash cards that teaches you foreign languages. Those were other USV investments from that time period. At the time, I had to think for a minute to realize that Stack Overflow has “gamification” too. Not a ton. Maybe a dusting of gamification, most of it around reputation. Stack Overflow reputation started as a very simple score.…