So Scala ranks behind the Lego Mindstorms language and Visual FoxPro in terms of community popularity? Sure thing. I know that valid results don't always conform to expectations, anecdotal evidence and intuition; there's a believability limit, though, which is being crossed here. TIOBE may be measuring its thing correctly , but in that case it's measuring the wrong thing.
See: http://www.tiobe.com/index.php/content/paperinfo/tpci/tpci_d...
It's easy to see how this measures the wrong thing. A better metric for me is the popularity of languages in open-source software, which could be measured by (say) the number of popular/active projects.
For instance take a look at: https://github.com/languages ... but this also has flaws, because GitHub is favored in the Javascript/Ruby communities and open-source C#/.NET projects end up mostly on CodePlex, a lot of Java projects are hosted by Apache, a lot of Python projects are on BitBucket and so on.
So a better metric would be to aggregate the projects from all popular project hosting services and count them, with some kind of weight attached. So for instance it would be unfair to count the lines of code in the Linux kernel, but it would also be unfair for the Linux kernel to have the same weight as some random project on GitHub that's being watched by 5 people. I would make this weight proportional to the number of active contributers, such that when a project is left unmaintained its weight will eventually drop to zero.