The market for web server software doesn't show a lot of variation these days. If you name a popular site, there's roughly a 50 per cent chance it will be using Apache.
Server picture from Shutterstock
Each month, Netcraft auto-polls active web sites to determine which server software they run. For its April 2015 survey, three platforms dominate: Apache, Microsoft IIS and nginx. (Google is a very distant fourth). These are the core figures:
Because web sites are often deployed and then ignored, those figures don't necessarily tell the whole story when it comes to servers that are being actively deployed or maintained. Netcraft also runs a survey across the million most popular sites, which presents somewhat different figures but maintains the overall order:
In other words: if you've built up skills on any platform other than these three, it's time to retrain, and if you're thinking of building your web server administration skills, Apache is the obvious choice.