This definition of social media is new to me as well, thanks for sharing it. This sort of clarifies a term I really dislike, and which you've used: "the algorithm". It's always seemed a little murky to me which algorithms it refers to. It's like saying "don't eat food with chemicals in it".
Lemmy does have "an algorithm", it's just a relatively simple one based on communities one is subscribed to plus some vote/comment data for the various sort orderings.
Lemmy also absolutely implements a social graph -- the data about who has interacted with whom is all stored by the system. It's not explicitly stored as a graph structure, but then we're arguing database schemas.
As I understand it, however, you're saying "social media" arises when the "social graph" data structure is used as an input to "the algorithm". That seems like a pretty robust definition to me.
One bit of pedantry: user blocks on Lemmy are, by a general definition, a form of social graph, and they do affect what content people see. So Lemmy could technically qualify as social media by the definition I've written here. I'm not sure what a more precise definition could be that avoids this technicality.
So most phones since 2019 have builtin functionality to blare alarms, show messages on the home screen, and... fuck knows what else... at the sole discretion of the telco?
Curious if anyone here knows more about the mechanism that allows this, presumably it's some kind of standard? Will custom ROMs work with it or is this another in a long series of fuck yous to anyone daring not to patronise the Bay Area Douche Nexus?
Edit: I see, it's Cell Broadcast, part of 3G, 4G, 5G, etc. standards. I still wonder about the "un-opt-outable" part; is it just that most phone OSes don't provide an opt out or is it implemented in firmware somehow? Warning tones I can imagine being wired straight to the drivers, but a visual message seems like it'd have to have OS cooperation.