Okay, so to answer a couple of the comments:

Microsoft.com is not *actually* unavailable for over a day/year.  So I guess a little explanation of the number is in order.  As I mentioned, we measure availability via Keynote.  For an explanation of all of the gory details you can visit: http://www.keynote.com/keynote_method/keynote_method_main_tpl.html.  The short answer is that the Keynote agents hit our site from locations all over the world and consider the failure to render even a single .gif to be a complete failure to render the page.  Additionally, they do not cache any of the components so every test renders every component every time.  As we've found from this level of testing, 99.68% isn't too bad!  Comparing ourselves with other sites via Keynote that are at our scale (IBM, Google, Yahoo, MSN, AOL, DELL, Oracle, SUN) it's a tight race, but we're still in the lead. 

Second answer.  No, we do not run Microsoft.com on Linux.  Microsoft.com is 100% Microsoft technologies.  We do however, maintain relationships with some CDN (Content Distribution Network) providers to bring large content like downloads closer to the end points around the world and since we don't own their infrastructure, some of those do run Linux.  From a business perspective, these relationships make sense regardless of what they use and we are actively working with them to convert all or part of their networks (http://www.microsoft.com/presspass/press/2002/apr02/04-10AkamaiPR.asp) But,  all of the servers that make up www.microsoft.com run 100% Windows 2003 Advance Server.  All of our web servers run IIS6 and all of our database servers run SQL Server 2000. 

I'm actually really excited to see that people actually care about this stuff enough to ask questions.  I hope this helps!  Keep it coming!