A Google whitepaper called "Understanding the Modern Gamer" shows that gamer behavior can be tracked through searches, and shows that there is a link between searches and game sales. One of their key bulletpoints from the paper says that 84 percent of game sales can be predicted from our searches.
They found some pretty fascinating stuff in their tracking of searches for the top 20 games of 2010 and 2011. They used their data to create a model and found that if a game nets 250,000 clicks in the 10 months around its launch, it will sell somewhere between 2 and 4 million copies in the first four months.
Google gives a picture of what exactly is being searched for in this window. Most start out looking for official information from the publisher, like trailers and release dates. The searches transition to walkthroughs, tips and wallpaper after launch. Google found that game reviews are still relevant even four months after launch, as some are still trying to come to a decision.
The data also shows that gamers use their phones often. Before launch, they often pre-order or buy games via their mobile. After launch, 27 percent of all tips searches take place on mobile devices, presumably while gaming.