http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=9012518

This seems somewhat innocent at first, but consider the implications:

Microsoft's new format will almost certainly be patented. And if they manage to get this format into mainstream usage for web design, they would be effectively making the internet Microsoft-only.

A similar threat occured with the patents on GIFs, which has since expired. Lucikly the PNG format was there to compete.

While Microsoft's format is fairly unlikely to succeed, the fact that they are trying is something not to be taken lightly.