Hype. Generated mostly by the Internet, journalists, and gamers who – let's face it – don't have enough to do, it's one of the more entertaining aspects of the industry. But is crazy amounts of hype good or bad for gaming's stability?
The benefits are obvious. Hype expands visibility, which in turn expands the potential for sales. Beyond the particular title in question, it expands overall visibility; i.e., the industry steps into the limelight and starts to garner headlines amongst mainstream news sources. Hype can introduce interactive entertainment to those who have never called themselves gamers; it can put a commercial before a curious consumer who goes, "damn… that's what video games have become?" With more visibility and more money comes expansion and, ideally, stability.
But there's a dark side to the obvious. It often starts with hordes of journalists amping up hype with pointless headlines, designed specifically to create conflict between the always-vocal gamer groups. At some point, a fair chunk of gamers grow sour with the whole mess; they don't even want to hear the name of the over-hyped game. Plus, there's the theory that highly anticipated titles have strange effects on review scores: arguments can go either way; some say because the game is so popular, the critics are more lenient. Others claim the complete opposite is true.
Furthermore, let's not forget that only one or two titles (as is the case with the current MW3 vs. BF3 war) can overshadow a lot of games, many of which are worthy of more attention. Hence, those overshadowed products don't sell well, innovation may take a hit (especially if the over-hyped games aren't innovative at all), and the industry starts to get into a rut.
Overall, hype has a significant impact on the industry, and while some say it's essential in some capacity, others will say it has nasty side-effects.