Yeah there does appear to be bias in their sample since Ruby on Rails was their most in-demand skill. Not to knock it or anything, but it hardly seems like the number one skill industry wide.
I think its naïve to rank skills by a framework or library, but we're talking about a hiring platform website, used by keyword driven recruiters. If they were being more honest and accurate, lumping Django/Node would seem more appropriate. JVM/Java + C#/MSFT seems like it could stand on its own as well.
