Well, in a sense, most of us all only know each other through our comments, and that's all we can ever base an assessment like this on. By proxy we have to assume that when people's inner thoughts leak out into the Internet on a forum like this (and in a sustained enough way to make them a top-100 karma earner) that their aggregate corpus of comments will be a reasonable insight into who they are.

So for all purposes that you, I or Watson can demonstrate, "do you think X is Y" and "do you think X's comments show Y" are functionally the same.

edit

I just checked what Watson thinks are my needs. Apparently I don't have many, and everybody on HN has an extreme need for Challenge.

I almost feel like these results require a lot of interpretation, and that interpretation is about as reliable as a horoscope.