Some of the statistics that you are seeking would be available from those of
us running web pages and using such services as "Pagecount" to serve as a
visitor counter.  Pagecount tracks the operating system as well as the
browser (if known) and provides the totals for the user.  It would not
answer all of your questions but might provide a useful beginning.  For
example, over the past month since I began a revised set of pages for our
museum the stats are as follows:

The Operating Systems of Visitors
Win 95   732
Win NT   74
Win 3.X   50
Mac   57
Linux   3
SunOS   13
Unix   3
Other   160

 Web Browser used by Visitors
Netscape 1   0
Netscape 2   31
Netscape 3   193
Netscape 4   303
Explorer   562
Mosaic   0
Other   3

proxy and Cache servers
proxy servers   3
Cache servers   11
Direct   1078

 I can supply longer term statistics of the same kind if desired but I have
found the ratios to be about the same.

Bob Wood  [log in to unmask]
The Space Center
Alamogordo, NM
http://www.zianet.com/space