As a follow up to Online Reviews and Small Businesses, check out this posting about the J curve of ratings. The most salient paragraph is:

Across many clients in diverse industries this “U” curve turns out to be more like a “J” curve…almost a reverse “L”. The average rating across all clients is 4.3 out of 5 stars. The distribution looks like a J, where there are more 1s than 2s, but far more 4s and 5s than the lower ratings.

It could simply be that mostly happy customers will fill in a survey, but it looks like there is little downside to enabling online ratings. The goal of online surveys being, frankly, not only getting the “truth” but also spreading the word.