Well, people use Netscape because Internet Explorer is not available for all operating systems. Netscape is available for almost everything.
Most Linux distributions come with Netscape pre-installed and Internet Explorer is not available for Linux (as far as I know).
Solaris is supported though.
Badly written HTML normally works in Internet Explorer whereas Netscape just doesn't deal with it. You might think this is a good thing, but it really isn't if you think about it.
Remember, there are other browsers out there and what suprises me is that people use them!
Opera is fairly common but wierd ones like QNX Voyager will come across your site from time to time.
It's worth making your site compatible with everything if possible or you cut out a lot of people. You might think it's only 10% or whatever, but 10% of 1000 hits is worth bothering about.
[ August 10, 2001: Message edited by: Stephan ]