Nearly half of all teenagers bought no compact discs in 2007, accelerating the music industry’s painful transition from CDs to digital downloads, according to a report released today.

One big beneficiary: Apple Inc. Its iTunes music store, which sells only digital downloads, jumped ahead of Best Buy Co. to become the No. 2 U.S. music seller. Apple trailed only Wal-Mart Stores Inc., which mostly sells CDs.