For me, there's a very simple distinction. The large sites are anti-social media; they use the pretext of facilitating communication to interpose themselves between people and siphon off their data, like if you're trying to have a conversation on the street or at a party and some creepy person is trying to listen in. LFGSS is a social medium, as the owner doesn't try to exploit the data, and so it genuinely facilitates communication (except when the subject of pie vs. crumble comes up and all gloves are off). The rest of the Internet is an increasingly negative place by comparison.
For me, there's a very simple distinction. The large sites are anti-social media; they use the pretext of facilitating communication to interpose themselves between people and siphon off their data, like if you're trying to have a conversation on the street or at a party and some creepy person is trying to listen in. LFGSS is a social medium, as the owner doesn't try to exploit the data, and so it genuinely facilitates communication (except when the subject of pie vs. crumble comes up and all gloves are off). The rest of the Internet is an increasingly negative place by comparison.