[kodfodrasz]

SO popularity is neither clearly positive, neither clearly negative.

Why not positive: because if there are lots of questions about something, it must be very hard, with lots of gotchas, unclear points.

Why not negative: because if there are lots of questions about something, it must be very popular, so many newcomers have their trivial questions, which do not necessarily indicate problems about the language.

[weberc2]

Right, the SO value is approximately the product of popularity and difficulty; the GH value is approximately popularity, so if you difficulty is approximately SO/GH.

[kodfodrasz]

If this would be true, then "XML" and ASP would be the hardest languages. Also this would suggest that TeX for example is simpler to use than Python or Ruby.

I do not think this stands.

[weberc2]

Hence, "approximation". In particular, XML isn't a programming language, so questions about it are more likely to pertain to writing parsers and the like. TeX users may well have other sources for answering their questions. The approximation is very rough, but there is clearly a signal in the noise.