Open source royalty and mad kings
world.hey.com
world.hey.com
I see this mentioned all the time, but what it's really saying is 50% of all WWW domain names have an associate WordPress install.
The stat doesn't factor in where internet users actually spend their time. For example, Meta/FB has a few WordPress installations, but its users spend less than 0.1% of their time consuming content served from those WordPress instances.
It also doesn’t factor in where non-internet users spend their time. This article about Matt Mullenweg doesn’t even mention spelunking or monasticism, which further impact the relative importance of Wordpress.