I don't think the number of questions asked correlate with which languages are used the most. My weekends are mainly Java, but I don't need to post on stack overflow because all of my questions have been already addressed.
What really makes sense. SO format does not suit Haskell very well.
Hoogle will already tell you most of what you can learn to small, fact-focused, objective and unanimous explanations about real code. SO intellectual avoidance rules hit much before people can explain anything useful.
I guess newbies will find some of the compile messages hard to understand compared to more standard languages, however.
That's why the post works in ratios of weekend to weekday. Regardless of how much more or less likely someone is to ask about one language than another language (e.g. because they're already familiar with it), the numbers in the OP should still indicate relative usage amounts at different times.