this scenario has literally never happened. I wish I could downvote this stupid comment because it's moronic.
For more than a handful of clients you were required to purchase a much more expensive server edition which was basically the same, but included IIS, Microsoft's web server. In other words, to legally use Netscape's (or anyone else's) web server on Windows NT, you still had to buy Microsoft's web server.
See also: http://www.landley.net/history/mirror/ms/differences_nt.html
It's very similar to what happened with Netscape, except they simply prohibited it rather than increasing price because of it.
Our company sued Microsoft over it. There was a settlement.