In editing a story on the shootings this week on the Indian reservation in Minnesota, I changed a reference to "a horde of media" descending upon the reservation to "a media horde."
What's the difference? Well, one makes sense and one doesn't. If you insist that media is and always will be a plural noun, you're stuck with the meaning of "more than one medium." Even if a medium in this sense (the concept of television? the concept of radio?) could swarm an Indian reservation, there aren't enough of them to constitute a horde. Media in this case is short for news media, so you have probably four: print, radio, television and the online world. Subdivide those all you want -- you won't end up with more than a dozen or so. Hardly a horde.
If, like me, you recognize that media when used that way is a mass noun, you see that horde of media makes even less sense. You wouldn't say horde of military or horde of judiciary, but military horde and judiciary horde -- and media horde -- are fine. It's a horde of people from the media, which works whether media is singular or plural.