The number of unique visitors to Apple's iTunes Music Store website reached 20.7 million in December, up from 6.1 million a year ago - an increase of 241 percent - according to Nielsen/NetRatings, reports InternetRetailer. The traffic consists mostly of teens, with those age 12-17 nearly twice as likely as the average web user to visit iTunes.

Males are more likely to visit the site, accounting for 56 percent of visits. iTunes visitors tend to favor the Volkswagen, Audi and Subaru car brands, watch the Cartoon Network 1.4 times more than the average consumer, and prefer Wired and Rolling Stone magazines.