This is a good measurement of what languages people on Github use, and which languages people on StackOverflow are having trouble with. They mention Go, for in

This is a good measurement of what languages people on Github use, and which languages people on StackOverflow are having trouble with. They mention Go, for instance. I write a lot of Go. I put it all on Bitbucket. I've also found that questions about Go are best answered on golang-nuts or in the IRC channels, or in the documentation, rather than StackOverflow. It's a pretty cool plot, as long as you take it for what it is: a representation of how many repositories exist on Github, and how many people are asking questions on Stackoverflow. In terms of measuring language popularity, it's about as useful as TIOBE.