OK, cuz I love you guys, I'll provide an honest answer:
I buy a lot of books, but I don't write reviews because I'm selfish, lazy and it would require a lot more feedback than what seems typical for the investment of my time. Plus, I greatly enjoy the interactive experience of discussing the books on the messageboards.
I wrote a review here once ( the first review for the Penumbral Pentagon ), and it was a good experience. I think everyone should try it at least once, as it can help you better understand your own rational for product buying/usage decisions.
Some other rambling thoughts, some of which echo ideas mentioned in previous posts:
If I am investigating a product for possible purchase, two or three reviews is more than enough research. Maybe only one, if I have developed a sense of a particular reviewers style and tastes. That being said, I have been relying on reviews less and less to help me make buying decisions. Most products get either a 3 or a 4 rating, so that doesn't tell me much. Neither does the Table of Contents style of review with most of the text just DESCRIBING what the book is. IMO, the real value of a review is relating what the product has to offer that is new, better, or different - what type of person might enjoy or appreciate that - Suggestions for use and compatability with other products - Direct comparisons to similar subject matter from other books, etc...
I'd like to have a place where people could go to request a review on a particular book that hasn't been reviewed yet. Maybe these requests might prompt someone who otherwise might not write a review to try one.