If you take a look at Netcraft's most recent survey, the leading servers on the Internet for active domains are Apache (59%) and Microsoft (34%), with the rest of the competition picking up the remaining crumbs.
Alexa top 20
But, you know, the Internet is a big place and some stats can be influenced by the choices of hosting providers. How does this data relate to me and what I should care about? Well, taking inspiration from someone measuring downtime of the Alexa top 20 sites, I checked the top 20 to see what server they ran.
Other than the sites running Apache or IIS, every other site runs a different server or disables the server header. What's interesting is that the competition to Apache and Microsoft amounts to a significant amount -- much different results than what Netcraft's results show.
Market share depends upon the market, well duh
Everyone knows that Microsoft dominates the desktop market with over 90% market share. So I was slightly surprised when I saw about 50% Macs at a RailsStudio event in late 2005. Even more surprising was the 90% Macs at RailsConf 2006 -- scenes like this were the norm. Macs dominated so much that I don't recall seeing a non-Mac and somebody awarded certificates to non-Mac users.
So what should we take away from that? Well Macs have high market share amongst the Ruby/Rails geek crowd and small market share amongst the general population. I'm a Ruby geek and already had a Mac ... but if I hadn't, I sure would've been checking them out.
5.9 out of every 10.0 geeks, choose Apache
The closest equivalent of a Ruby/Rails peergroup in this situation might be a sampling of sites that I visit. So I sent my Haskell web crawler out to about a hundred sites and got the following results:
Apache dominates as expected. But Microsoft-IIS has much less market share than in the other surveys. Lighttpd and mongrel show up as having measureable market share, whereas they were invisible in the other surveys. Lastly, the other category is still significant competition and includes a rich variety of servers, including ones running Lisp, Erlang and Haskell.
Basically this puts some stats behind my perception that Microsoft is a minor player in the web server market and that some small upstarts like lighttpd and mongrel have made good progress in the geek community. YMMV.