I've found it to be pretty crap at doing things like actual algorithms or explaining 'science' - the kind of interesting work that I find on websites or blogs. It just throws out sensible looking code and nice sounding words that just don't quite work or misses out huge chunks of understanding / reasoning.
Despite not having done it in ages, I enjoy writing and publishing online info that I would have found useful when I was trying to build / learn something. If people want to pay a company to mash that up and serve them garbage instead, then more fool them.