"End users shouldn't know what a "codec" is, they should double-click a file and see it play, which is what VLC is all about."
This statement is what's made all the headaches of computers happen.
People using computers, especially online, should be required to pass a competency test and basic knowledge test.
Well, sort of. What's made codecs an especially thorny hassle on both Windows and Mac has been the operating system's staunch absolute refusal to admit that they exist, and to give the user any kind of relevant feedback whatsoever, combined with both companies' equally staunch refusal to allow codecs to be distributed freely.
For example, right-click on a .wmv Explorer on Windows 7. Go ahead, I'll wait. Now, let's see what metadata we've got in the details pane. Hmm. Title, Subtitle, Rating (huh?), Tags, Comments, Length, Frame Width, Frame Height... more esoteric stuff, like data rate, Total Bitrate.... absolutely no mention of codec. Go look under Control Panel for anything about installed codecs. Nothing. (For extra credit, go digging through the raw Registry looking for information about codecs... it's certainly not well documented). So how's even a trained user supposed to understand what she has or hasn't bought the rights to use on her system?
Codecs could be sensible, if they were treated just like programs, file extensions and fonts: things you could easily tell existed, and if they had a neat control panel somewhere showing what was and wasn't installed. But for inexplicable reasons, all the major OS manufacturers seem to have conspired to make codecs both invisible, and yet sold as commercial extensions that you can't just assume are there. Bizarre.