I was asking myself if the intention is to state that it's one of the website nobody knows most visited one (in the list of website nobody knows) or just pure clickbait.

As the first possibility is impossible to nkow (if nobody knows about them...), I agree with you and vote clickbait !

Yes, but the article makes clear that the content is spread across many different .TLDs (possible reasons for this are offered in the article) which combine for 100 million monthly page-views.