The domain names can be reused. 3 days after the domain names are created, both the domain name and the feedback comments are hard deleted. Since it is a hard delete, there's nothing that stops the domain name from being reused again.

I thought about this a bit and I can see this being confusing and possibly dangerous though. For example if somebody shares a domain they created, and 3 days later somebody visits the domain but it's a totally different domain.

Thanks for pointing this out! I will think about some ways to solve this.