Whatever domain name is cheap is going to be plagued by spam.

I think in recent time, .icu and .xyz have been the most problematic, to the point where you to this day probably don't want to host a mail server on those domains.

The same with cloud providers. A fairly significant amount of sketchy websites seem to be hosted on cheap cloud providers with weak rules enforcement. I've taken to blocking all of Alibaba's IP ranges from my search engine crawler, the signal to noise from those sites were so bad it just wasn't worth looking for legit content.

Just, no. Plenty of legitimate websites under .it, basically every single Italian company plus all localized versions of international websites (apple.it, google.it, ...)

Why? .tk was popular because it was free, so it was really useful for teens and young adults in an era when you still had to host things somewhere if you wanted them online. On the other hand .it is the tld of Italy and used legit by all businesses of EU's third largest economy.

Shame too. I was hosting my personal site on .tk when I was broke out of college, but often a link too it was automatically flagged as spam.