Dunno if they pay, but it seems to be the case that those do use IIS. Response headers from one of my GoDaddy parked domains:

    Server:Microsoft-IIS/6.0
    X-AspNet-Version:2.0.50727
    X-Powered-By:ASP.NET

Godaddy.com also runs on IIS, so it may just be a company/cultural preference.

I once worked for a company that had a large Java-based application. Microsoft (a then client) demanded the application should run on IIS and be written in .NET or they wouldn't hire us.

That may be part of the deal.

Note: We wrote an IIS-based proxy that masked away the Java-ness of the application and replaced it with .NET-ness. Worked perfectly.

GoDaddy is one of the major .Net shops in the Phoenix area. As far as I know, they're predominately .Net.

I wonder how many of the 59,646,778 are parked there.

Must have been expensive.