Back in the day when I was more of a whore, I never asked if I was fucking them. On the occasion I was going to bottom, I was more likely to ask their status, but not always. Now that a lot of guys are on PrEP, and U=U has been scientifically proven (I have been undetectable over 20 years) I typically don’t discuss, unless they bring it up.
the only hookup site I am on now is BBRT, so in my opinion, I assume most everyone online doesn’t care, but I do list my status as undetectable usually.