Digital music purchases accounted for 50.3 percent of all music sales in 2011, marking the first time digital sales have outpaced physical album sales. According to data released by Nielsen SoundScan, digital sales were up by 8.4 percent from 2010, while physical album sales declined by 5 percent.

Adele, the top-selling artist overall for 2011, was also the best-selling digital artist, with her album 21 moving 1,801,000 digital copies (out of a cross-format 5,824,000 total) and her singles "Rolling in the Deep" and "Someone Like You" selling 5,813,000 and 3,750,000 downloads, respectively.

Other big sellers in the digital album format include Lady Gaga (whose Born This Way was given a significant boost by a deep discount sale on Amazon in the week of its release), Mumford & Sons, Jay-Z and Kanye West's Watch the Throne, Lil Wayne and Coldplay.

On a larger scale, digital music consumers favor the rock and alternative music genres, with rock albums accounting for 38,593,000 in digital sales, and records classified as alternative - a rather vague genre designation – moving 24,674,000 digital albums overall. R&B is the third most popular genre for digital album downloads, followed by rap, metal and country. Unsurprisingly, the pop genre leads the way for digital track sales, with 24 percent of the total market, followed by rock with 22.9 percent and R&B/hip-hop with 20.6 percent.

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