Sure you can. Click a user, see their comments, submissions.

I would say hn is in a group of systems that include Facebook.

It's true that contemporary commercial social media tends to be associated with these big corporate services that have already been thoroughly enshittified.

But they didn't start out that way - and alternatives are possible and desirable (hn, lobste.rs, many niche forums, IRC channels, discord servers[d] etc are proofs by example).

Maybe a loose definition would be communication system that leverage the network effect?

And good social media aligns with the end-user, and bad aligns with user-hostile forces?

[d]: (I don't particularly like discord, but it is much closer to a tool that does what I want: connect with people - than something like tick-tock or Facebook as it exists today)