On: Chrome 56 Beta: “Not Secure” Warning, Web Bluetoot...

[kuschku]

If you want to have a signup process that takes less than 9 hours, you have a max of 20 new subdomains a week.

20 users signing up a week - likely with a retention of a few percent - is not a "large hosting provider".

You might have a few hundred users max, and already will be far over the rate limits.

[Ajedi32 → kuschku]

Just start them off with HTTP and transparently upgrade to HTTPS after 9 hours. And if you're only retaining a small percentage of users who sign up, you can stretch that limit even further by only upgrading the users who you retain.

[Sephr → Ajedi32]

This isn't possible in a properly deployed HTTPS site, since it would already have an HSTS header with includeSubdomains.