I feel we've got used to the idea of global reach and that you're participating in a conversation with millions of people. Except that doesn't work very well, even if a 'global conversation' would seem like the end goal, and then to filter that firehose you need some kind of algorithm that adds its own biased etc.
Here I think it's actually more 'social'; interacting with real people, with the *potential* that anyone globally could join in, but mostly that doesn't happen and it's just you and your friends. And that works much better for people.