The best algo is one of the very first ones invented. It's called reverse chronological and shows you the stuff that's newest first and older as you scroll down. That way, as soon as you get to stuff you've read in the past, you can stop reading and move on with your life.

Corporations can't have that because they need you to see more advertising and stay on their service longer and therefore they fuck you over and make you not know whether you've actually seen everything or not so that you can't click off.