The story of podcasts suddenly being “back” strongly suggests, and mostly requires, that they had been big at one time and had since gone away. That New York Magazine article even cites a “bottom” time: 2010. But that never really happened.
Podcasts in 2010 were a lot like podcasts in 2007, which were a lot like podcasts in 2004, which are a lot like podcasts in 2014. There’s a lot of tech shows (and a lot of tech listeners), but most of the biggest are professionally produced public-radio shows released as podcasts, with other strong contingents in comedy, business, and religion, followed by a huge long tail of special interests with small but passionate audiences.
All I ask is that anyone who is suddenly into podcasts because of Serial give this a read.