CNet has a helpful article on how to spot fake product reviews. It is oriented toward tech products and not books, but Amazon has a serious problem with fake book reviews. For Bookwi.se, I tend to rank the free books that I post by number of reviews and how positive the reviews are. This is the easiest way to be able to help readers find the books that are most likely to be good. And when there are dozens of reviews, it tends to not make a lot of difference if there are some fake reviews. But for many free books, there are less than five reviews. And one or two fake reviews can sway people to look at a book.
Other than CNet’s suggestions–1) all good or all bad, no balance, 2) not using a real name, 3) lots of reviews on the same day, 4) the reviewer only reviewing that one product, and 5) the tone of the review–what suggestions do you have for spotting fake reviews?