IIS capacity - a few questions

(This is probably a stupid question but I haven't had to think much about
this before.)

My manager has asked me what the maximum number of users on a web app can
be. I'm embarrased to admit I don't exactly know how to answer this. So I
started digging.

Of course users connect only briefly to the server at any given time. First
of all assume plain vanilla Intel boxes running Windows Server or Windows XP
Pro. Ignore for the moment questions of processor speed and network
conditions.

I see that TechNet states
(http://technet.microsoft.com/en-us/library/bb663573.aspx) that IIS6 has a
default of 8000 'connections'.

Does this mean (in ASP.Net terms) that IIS6 can have 8000 application
sessions, or does it mean that 8000 users can be requesting a page or posting
back at any given instant? (And what would this mean in a non-Dot Net
situation?)