Ah. This hits home. My software finds and downloads movies and other files from Usenet and one thing that really burns people up is when they download a 100MB avi file only to find that Windows Media Player can't find the codec. Has WMP ever found any codec for anyone ever? I've never seen it happen.

Second problem is the ever so fragile avi format itself. Unlike with mpeg files, if just one part of the avi file is damaged or missing, the entire thing becomes unplayable. With mpegs, users are able to download the first part of the file, play it to preview it and then decide whether they want to download the whole thing. The mpeg format can be as torn up as a block of swiss cheese blasted by shotgun and it will continue to work as long as the first part exists.