Analyst Jesse Divinch of EEDAR has suggested that when it comes to selling games, good advertising and marketing is more effective than good review scores. Feeling incredulous yet? That's hardly surprising, as you likely take your gaming seriously and aren't going to let yourself be swayed by some flashy ad campaign.
Unfortunately, if you're reading this then you are not a typical gamer. The ubiquity of the internet makes it easy to assume that everyone is as well informed about games as you are. Trailers, interviews, previews and ultimately reviews are available from a wide variety of sources and not exactly difficult to find, so surely everyone reads them, right?