In one word: Compression.
The way the video is put into a digital format is night vs. day to a software package. Not to mention, the application of these 2 formats is opposite ends of the same spectrum....
When a development team tackles the idea of making video available to the user, they ask themselves questions based on ease of use and distributability.
Now, AVI should be out of the question in my opinion because WMV has taken it's place. The AVI came out in, what, '95? And when was it last changed? I think we're up to v9 with WMV...
May I ask what the reason for this question is? What are you trying to accomplish? Please elaborate as much as possible, I'm sure Dani won't mind. ;-)
Unsolved 
