After Kid Roc's Rock N Roll Jesus enjoyed a sales boost thanks to hit single "All Summer Long" — which isn't available on iTunes — Warner Music attempted a similar strategy with their new artist Estelle, who had a Top 10 hit at the time with "American Boy" (which features Kanye West). Estelle's album Shine was pulled from iTunes — and then the song and album both plummeted down the charts. "American Boy" dropped from 11 to 37 on Billboard's singles chart. On the download chart, the song has fallen from six to 59, and a cover version of "American Boy" by the Studio All-Stars is outselling Estelle's own version due to its availability on iTunes. The backfire has Warner considering whether they can reach a deal to sell only full albums on digital-music services, as opposed to single songs (iTunes discourages labels from selling full albums). The "American Boy" decline also spotlights iTunes' dominance, since Estelle's song is still available on Amazon, Napster and Rhapsody. The Wall Street Journal reports that iTunes sells 90 percent of digital music in the U.S., and is the nation's largest music retailer (besting even Wal-Mart).