Here's another survey of Web sites that has a more refined
search than the Netcraft survey of Web sites. Apache still
dominates the rankings, even with the finer-grained search
criteria. "The Security Space Web Server Survey is a survey of Web
server software usage on the Internet broken down by 86 domains.
Security Space estimates that even though there are almost 20
million Web sites, nearly 90 percent are 'orphans' to which no
other sites link. Security Space's Web server survey includes only
those servers referenced on other sites."