In order to make a proper decision, the customer must be provided with a proper information. Advertising is not such a proper information, it is a part of information at the best. Reviews in computer game magazines have been, possibly, a part of the advertising campaign for the product. The customer, seeking information, could turn to the internet fora like this one but it seldom happens. Moreover, the official forum displays only the part of the information of the product (its positive side) while hiding the other part (deleting the posts on bugs), thus it can be considered a part of the advertisement campaign.
Disillusioned users of the product, posting their angry reviews on Amazon and other sites dedicated to selling, do a good thing, since they provide a potential consumer with a valuable information he would not obtain otherwise.