msn.com blocks non-Microsoft browsers:

http://news.cnet.com/news/0-1005-200-7655334.html

In addition, it looks like msn.com encourages users to upgrade to the
latest version of IE when accessing the site.  Since most people use IE,
and the default home page is msn.com, I can see how Microsoft can start
using msn.com to force users to upgrade their web browser.  Then they can
slowly start adding new features to the browser that lock users even more
into Microsoft-only sites/software/whatever.  I'm guessing that users will
soon have to sign up for a Passport account when browsing Microsoft sites
or using IE.  Then Microsoft can use the millions of people signed up for
Passport as evidence of it's success and then "encourage" other websites
such as Amazon and ebay to use it exclusively for their users.  The end
result will be an even more difficult time for people attempting to use
non-Microsoft software on the Internet.
~M