WHAT: Sony Corp. agreed to sell its Gracenote music database subsidiary to TV/newspaper conglomerate Tribune for $170 million, a 35% discount from the $260 million that Sony paid for Gracenote in 2008. The transaction is set to close by the end of March. Gracenote launched in 1998 gathering data on CDs and vinyl albums. It's since branched out to TV shows, boasting a database of 180 million music tracks and TV shows. Apple uses Gracenote to identify CDs that people copy to their iTunes libraries.