I called up the patent on the US Patent Office's web site. Here's the link to this patent:
http://patft.uspto.gov/netacgi/nph-P...;RS=PN/6041345
Apparently the .ASF format incorporates some new technolgy or technique for coordinating multiple data streams. They're not just patenting the format, but it's way of accomplishing what it does.
The .S3D format doesn't do anything new, and any patent claim would last about ten seconds before someone shouted "prior art". It doesn't have anything on .ZIP (or even .ARC for that matter).
This is what I mean by "you can't patent a file format". You can only patent a technology, not a particular implementation of that technology. For Microsoft fo patent .DOC, the .DOC format would have to include some novel technology ("invention").
WC