Actually the Obamacare site is hosted on Akamai's Linux servers, which are ultra-reliable, and a good choice for large sites. Some years ago, Microsoft's main site microsoft.com, which of course was hosted on Windows servers, went down unexpectedly due to server problems, and while they got it running again, THEY hosted on Akamai's Linux servers (causing no end of guffaws from the open source community).
So, the Obamacare site being "down" doesn't mean the hosting servers are in trouble at all. It means this is the first of many downs while they try to figure out what the heck they're going to do with all the broken SOFTWARE on the website.
That's where the trouble lies.
... and the problem with the website SOFTWARE is that it's written in Microsoft 8K BASIC.
I find it interesting that companies like Google, RedHat, and Oracle are sending in “gurus” to help out.
Because every floundering mega project needs a few more egotistical generals to direct the troops....
Microsoft used to run their HR/Payroll on an IBM AS/400