Research from NPD Group claims that active Twitter users buy 77% more digital music downloads on average than non-users. 34% of all Twitter users have bought digital music in the last three months, compared to 16% of non-Twitter users, according to the survey. Oh, and they’re twice as likely to visit MySpace Music and Pandora as average web users.”Based on their music-purchasing history, active Twitter users are simply worth more to record labels and music retailers than those who are not using Twitter,” says analyst Russ Crupnick. In truth, the results aren”t startling – Twitter users are by definition fairly tech-savvy.However, it does provide more evidence for Twitter’s potential for artists and labels. “But it has to be done right,” says Crupnick. “There must be a careful balance struck between entertainment and direct conversation on one hand, and marketing on the other.”