I offer my podcast as MP3 and OGG format since the beginning. I chose to use OGG (additionally to MP3) because of the MP3 licensing issue. But meanwhile I found out that there are no patents any more on MP3 since 2012 (at least according to Wikipedia).
The Podlove analytics show that 89% of the listeners use MP3 and only 9% the OGG format. Thus, I think about dropping OGG again since offering 2 formats means also using twice as much disk space.
What do you think about this topic?