The venerable NPR program Car Talk has stopped providing streaming versions of their programs in RealAudio and has switched instead to Windows Media Player. As noted in the comments from the site, you can access WMP from the Macintosh, so they aren't cutting Mac users out. Interesting (and hopefully informative to the Real Networks folks) is the solid rant explaining why they switched.
The basic issue is that the folks at Real Networks have created a site for downloading their free player that is so confusing that many of the Car Talk users complained they had to pay for the player.
While not true that they have to pay for it, the design of the site is so manipulative, I can completely see why people end up getting charged or leave in frustration.
The folks at BoingBoing indicate in a snippet that there is even a special page for downloading the version for BBC users, because the BBC News folks wouldn't commit to using Real Networks' software without such a page.