New York Public Radio’s WNYC recently beefed up its mobile app with a personalization feature allowing users to generate playlists of news content that can be downloaded for listening on the subway or places where their phones go offline. The “Discover” feature of the WNYC mobile app lets listeners curate stories about topics that interest them — such as technology, pop culture or movies — into playlists of lengths ranging from 20 minutes to three hours long. The app pulls both local and national news stories, downloading batches of segments for later listening. The feature was designed to target the city’s subway riders, said Thomas Hjelm, chief digital officer at New York Public Radio. “It started with the thought, ‘Wouldn’t it be great if there was an app you could use for a 30-minute subway trip?’”, he said.