What the blue blazes does this mean?

A long time ago – make that a very long time ago – I had a German master at school whose favourite expression was “what the blue blazes do you think you are doing, boy?”, at some impropriety.

Well, in a different field, I read the following comment on the housing market. My question is: “what the blue blazes are you saying about the housing market” Because I have no idea. (more…)