The official Slackware Linux website is hosted on Ubuntu
A few years ago I speculated in the article “Slackware Linux trivia, history, and things you didn’t know” that slackware.com was being hosted on Slackware Linux 12.0. My assumption was based on the host headers returned from the server. Those headers reveal that the webserver is Apache/2.2.22, coincidentally the last Apache patch ever released for Slackware 12.0. However, it turns out that I was very wrong.