Marketing Vox reports that NPR’s site traffic is up 78% over the last year, thanks in large part to podcasting and social networking features. NPR.org had 2.6 million unique visitors in August, a 78 percent increase from a year earlier, according to comScore data.

Public radio audiences and contributions went up, too.

NPR is also planning new social networking and podcasting features:

• Listeners can create personal profiles containing photos, and list their favorite books, movies, NPR programs, and local stations. Like Facebook and MySpace, they’ll be able to declare themselves “friends” with other users, including NPR staffers.
• The station is also expanding its API library so local radio stations, and ordinary people, can incorporate its content into their own applications. One tool plots the subjects of NPR stories on a world map. Another lets people listen to stories on iPhone.
• NPR also plans to increase the flexibility of its podcast downloads, which have tripled in use over the past two years.