Minecraft led to Persson becoming one of "Forbes" "World's Billionaires". "Minecraft"s music and sound effects were produced by German musician Daniel Rosenfeld, better known as C418. The background music in "Minecraft" is instrumental ambient music. On 4 March 2011, Rosenfeld released a soundtrack, titled "Minecraft – Volume Alpha"; it includes most of the tracks featured in "Minecraft", as well as other music not featured in the game. The video game blog Kotaku chose the music in "Minecraft" as one of the best video game soundtracks of 2011. On 9 November 2013, Rosenfeld released the second official soundtrack, titled "Minecraft – Volume
Minecraft and has never been commercially advertised except through word of mouth, and various unpaid references in popular media such as the "Penny Arcade" webcomic. By April 2011, Persson estimated that "Minecraft" had made €23 million (US$33 million) in revenue, with 800,000 sales of the alpha version of the game, and over 1 million sales of the beta version. In November 2011, prior to the game's full release, "Minecraft" beta surpassed 16 million registered users and 4 million purchases. By March 2012, "Minecraft" had become the 6th best-selling PC game of all time. , the game has sold 17 million copies