This chart shows the history of detected websites using Medium
We detected the following sites were using Medium
HTTP headers, including cookies, can be used in same situations to identify a CMS.
If a CMS doesn't have meta tags, it will often have other uniquely identifiable html markup. This can range from unique html comments, ids or classes.
Some content management systems also offer hosting. A website hosted on a CMS developer's domain is a dead giveaway.
Dedicated Content Management System Detection