Also note the inverted shape of the trends: Apache is much more popular among less visited sites, but gets less so as you go up. nginx is unpopular with the mas

Also note the inverted shape of the trends: Apache is much more popular among less visited sites, but gets less so as you go up. nginx is unpopular with the masses, but more so with the most popular sites. I can see at least two ways to interpret this: 1. nginx is just strictly better, and the sites at the top need that performance/capability and employ the top/best-informed architects to maintain their systems, so they're the early adopters. Everyone else is still on Apache by virtue of inertia, but will slowly move over as time goes on. 2. nginx is faster for high concurrency, and mostly gets used as a front-lines layer in front of something else, maybe even Apache itself. In this case, the charts will stay about like they are now, because only the most stressed sites need that much engineering. I don't know that there's an easy way to differentiate between the two without either waiting and watching for change or knowing more about the internals of the top few thousand sites.