The number of NPR Podcasts nearly doubled this week with the addition of 16 new titles, including three original-to-podcast features under a new alt.NPR brand; more of the thematic podcasts, culled from NPR programming; and content from NPR's archives. NPR Podcasts made their debut on August 31 with Acura as sponsor.

The expansion comes just two months after NPR launched the biggest podcasting effort of any media organization, with its 17 initial titles generating 5 million downloads as of early this week and finding a place on the iTunes and Yahoo most-popular podcasts lists.

The three alt.NPR branded podcasts are "On Gambling with Mike Pesca," a weekly examination of gaming culture, trends and psychology; Groove Salad's "Taste of the Week," a selection of music from San Francisco's online music service SomaFM; and "Youthcast," public radio productions from up-and-coming young producers from PRX/Public Radio Exchange.

NPR's online-only "All Songs Considered" - the podcasts of which consistently rank among the Top 10 in ratings - offers "Open Mic Music," enabling new artists the opportunity to upload their work and have podcast users vote.