Filed under: Sony PlayStation 3, Microsoft Xbox 360To us, demos seem like a great way to get the word out about games, but a recent study suggests that they might be better tools for consumers than solid marketing strategy. The Electronic Entertainment Design and Research Group (EEDAR) reports that games that are marketed on Xbox Live and PSN with a trailer only sell considerably better than games that ship with a demo.On the PS3, games with no demo or trailer actually sold better than those...