Some statistics on the growth of Red Hat’s Fedora community-driven Linux distribution for web serving. Of interest to me as I used to administer and use some Red Hat web servers, though with Mac OS X on the desktop now I tend to use that for testing web stuff (e.g. various flavours of Movable Type are installed locally for testing and potentially to maintain a personal blog/database of research information).
Anyway, see Netcraft: Fedora makes rapid progress
For a breakdown of web servers by server type see March 2005 Web Server Survey Finds 60 Million Sites.