Nokia's got it's own "copy" of TuneIn Radio (with Nokia as the publisher).
It looks identical, but does have a higher version number than the regular/official version. (2.2 vs 2.1).
Release dates also differ (with the official one being "older").
One thought I had was that maybe the Nokia one was optimized for Lumias in some way. Another possibility was that the official app wasn't available in all markets.
Are there any actual differences/which should I be using on my Lumia?