The 'serial' podcast has nearly 1.3 million downloads per episode

"In the normally low-profile world of podcasting, “Serial” is a certified sensation—a testament to the power of great storytelling. It’s quickly become the most popular podcast in the world, according to Apple, and the fastest to reach 5 million downloads and streams in iTunes history. “Serial” is the top podcast in the U.S., Canada, the U.K. and Australia, and in the top 10 in Germany, South Africa and India.
[...]
“Serial” is downloaded an average 1.26 million times per episode, sending fans into debates over the finer points of the evidence. People can hear the podcast, which is like a radio show but entirely on the Internet, either by streaming it from the “Serial” website or downloading it onto a phone, tablet or computer from a platform like iTunes."

Source:  WSJ, 13th November 2014