Tumblr have a url scheme where subdomains are user-owned. https://m.tumblr.com/ https://m.tumblr.com/ != https://tumblr.com https://tumblr.com When they initi

Tumblr have a url scheme where subdomains are user-owned. https://m.tumblr.com/ https://m.tumblr.com/ != https://tumblr.com https://tumblr.com When they initially decided to hide the "m" subdomain, https://m.tumblr.com/ https://m.tumblr.com/ was shwon as tumblr.com. It's not the only website with that issue.