Also, I don't know how it was in other countries, but I remember that pay-tv services in Italy didn't have ads during programs and films, but only between the programs. It was a way better experience.
People are downvoting you, but I remember going on porn websites at 9 years old and it was great. I turned out fine, and I'm glad my parents didn't check my browser history.
You're partially right, I'd like to add some details: websites can also check if a domain (e.g. example.com) actually exists. So if you smash random letters on your keyboard and you end up with a non-existing domain, a website will be able to stop you from using that address.
More advanced websites also check for an MX record on the domain DNS. If a domain exists but it doesn't have an MX record, then it's not going to be able to receive emails and may be blocked in sign up forms.
Edit: not only an MX record, but also an A record, because if no MX record is present, then the mail is sent to the A record as a fallback (even though, in all honesty, I think this is a very uncommon configuration on the modern internet).
Yeah we need to go back to a curated list of content like back in the days of directories.