[hansjorg]

Not always, see domain fronting: https://en.m.wikipedia.org/wiki/Domain_fronting

[blattimwind]

Or services which use subdomains for individual users, e.g. #.github.io, #.tumblr.com, #.blogspot.tld and so on.

[cesarb]

This. Currently, the difference between accessing github.com/blattimwind and blattimwind.github.io is that, in the second case, which username you're accessing is visible to all. Encrypted SNI will also protect that part of the URL.