Before buying anything on-line I tend to read the reviews. Some are very helpful ~ some off-putting, and presumably with good reason when there are a great many 'single stars'. I write this bloggy note in order to help both readers and writers.
A great many comments are irrelevant, and destroy the credibility of the author ~ 'not as big as expected' (when size is clearly stated)
Some indicate fraud, and it is sad that most shop-organisers fail to take action. Most commonly I have found a cheap substitute is supplied, when a branded product from a reputable supplier is listed.
Some are slip-ups in the listing. These can be a useful warning for sellers, and it important that they are corrected, or better still written wisely in the first place. Common among these is 'This is only 20 pages, but was listed as 40' This is a caused by a reasonable misunderstanding of the word 'page'. The cure is to clearly state '20 leaves is 40 sides', and avoid the word 'page' altogether.