5by5 has an app, only recently released. Why would there be another one? Is the app 5by5 has the same as this Mule one? What is this Mule thing? Is it completely new?
Now we know what happened with that version.
Presumably, they were previously working with BlackPixel to do a podcasting app for the 5by5 shows, which was never released. The Mule Radio app appears to be a re-branded version of that unreleased app.
According to this tweet by Dan Benjamin about adding podcasting to the 5by5 app, he feels other apps already do it better. This may have been the reason why they scuttled their own podcasting app and went with a live broadcast app instead:
https://twitter.com/#!/danbenjamin/status/203466535107440640
So, Dan wanted an iOS app for some time now (year? more?) - and he was working with Black Pixel (http://blackpixel.com) on that.
We don't know exactly why, but that app was never released - Dan stopped talking about it (I'm not actually sure about this, somebody please correct me if I'm wrong.). Recently, he (again, not sure) wrote new app - that's what's on App Store as 5by5 app.
Parts of "old" app were apparently reused by Black Pixel while working on Mule Radio app (also by Black Pixel.).