But also, my experience in TAing the weed out course for the CS major (and from seeing my fellow TAs teach and work, who were more or less the best in class at my University--so much so that I was flown out by a company simply because of my involvement in that class) was that social skills had absolutely no correlation to technical ability: your ability to understand how pointers or complex data structures worked had absolutely no relation to how socially fluent you were. In fact, it often went the opposite way, up to a point: there was some base line of social fluency that everyone I worked with and the best people I taught seemed to meet. The single best coder I have /ever/ seen work (he alone makes me absolutely certain that the best people in our industry are 10x/100x more productive than the average) was also one of the most comfortable with people and had a very clear idea of his career goals. I'd expect him to give confident, unhesitating responses to "Where do you see yourself in 5 years?" and "What's your greatest strength/weakness?" Negatively weighting that would mean you'd miss the hands down most productive person I've ever seen work: and you'd probably miss a decent number of the other people I taught with. (Who, as I said, were basically the cream of the crop from the program I was in. Not all of the best people were there, but all of the people there were among the best.)

Now, I don't think they're particularly good interview questions, even though I understand why they're asked. I think that asking questions about actual workplace soft skills (conflict resolution, for instance) would be a much better use of everyone's time, since in the end it's those things that actually hold a team together.