I've heard of this before, but I'm not sure how I feel about it. There's a school of thought out there that speeding up the playback of podcasts results in more 'listening time' during the day.
Mathematically, I suppose it's hard to argue against that logic, but I have to wonder why the listener is listening to the podcast if it's all about cramming as much content into the day as possible.
As Twelve Black Code Monkeys says:
There are some downsides, but I don't think they are significant for most audio. One is that you have to pay closer attention, since drifting off a bit will mean that you will miss a lot more than you would normally, plus it just takes more concentration to comprehend everything at a higher speed
Right...so I need to focus all of my attention on the podcast. Seems to me that if I'm going to need all of my attention then I may as well watch video blogs, no?
Most of the podcasts I listen to fit into the entertainment category so I listen to them in the background. I think that listening to them 'sped up' would make them quite disruptive.
I guess if I was listening for education purposes, though, then being able to add more content to my day would be a benefit.