Treat the word algorithm as a "magic black box". Because that's what it is, 90% of the time. It could be that chronological sort. It could be a rage engagement sort. People don't know. It's not a consistent thing either, since pretty much every social site out there that people use is constantly tweaking it, A/B testing it, or having it modify itself to an extent (that is, I assume randomness is built in).

I do think the internet would be a better place with more openness about those magic black boxes, even if it's just an ability to tweak it yourself without having to do some arcane incantations and rituals (ever gotten your YouTube recommendations completely fucked? How do you unfuck them?).