Talking following the Activision results, CEO Robert Kotick reveals the Guitar Hero franchise is the third game in history to reach $2 billion in sales, criticizing a "rather precipitous [sales] falloff" for MTV's rival music game Rock Band. As part of the financial call, when quizzed on the Guitar Hero franchise, which Activision Blizzard continues to expand significantly, announcing several new iterations for this year, the company had several notable comments. In particular, Kotick highlighted increased market share in the music genre for Guitar Hero, criticizing the "rather precipitous falloff of [Rock Band]" as a retail franchise. (However, it appears that Rock Band 2 is concentrating on digitally distributed add-ons that aren't tracked via retail.) He also revealed that the Guitar Hero franchise has now reached $2 billion in sales, something that the company claims is the third in history, after Mario and Madden, to do so. He also noted that Guitar Hero: Metallica "is off to a good start", and it has a large installed base of peripherals to pick from now, since 15 million unique households now have Guitar Hero hardware installed. Given that the company also revealed during the call that 40 million "professional songs" have been downloaded (presumably both free and paid) for the Guitar Hero franchise to date, alongside 14 million GH Tunes "user-generated songs", it's easy to see why Kotick might conclude: "We're bullish on the music category." [UPDATE: Difference between professional, user-generated songs clarified.]