Thanks for your comments, Steve and Rob. I agree very much with what you're saying. I've noticed that in my class evaluations vs rate my professor. The class evaluations, which everyone has to do, are almost always mostly positive, with only the occasional ingrate who really sounds off. If you check rate my prof, though, you'll find much more of the negatives, since people who really hate something are more likely to seek out a way to do damage than people who like or even love it. I've heard the same is true for those referral/comment type services; the people who fill out comment cards in restaurants want to complain, not praise.