I just felt like mentioning this earlier but didn't. fanbaby, see you are wrong.
As you can see. IIS is go.ing places, like go.com places. And not just go.com which seems to be a glorified RSS feed with a Yahoo search bar. No siree. It's also powering conduit.com, which provides a pretty amazing "social toolbar" that I'm sure you will all install because it won't do anything bad to your computer.
This is honestly more pathetic then I thought. I could have sworn more people used IIS, wasn't it just behind Apache at some point. Weird.
EDIT: Stackoverflow is IIS for sure, and it's a Real Site. Rejoice! So it's not the end of the world or anything.
IIS (indeed any Windows setup) costs money to install. Most startups are smart and broke, so they know they can do the same for (more or less) free. That doesn't mean IIS is a bad server, it just means that it costs money.
The fact that StackOverflow runs on IIS is actually a pretty good ad for its robustness IMO