It's a straightforward idea, though the #SpamWars brought in an important modification: the message should be *consensual* (DoS attacks, spam, etc don't count).
The degradation of the internet into "five giant websites, each filled with screenshots of text from the other four" (h/t @tveastman) meant the end of end-to-end.
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If you're a Youtuber, Tiktoker, tweeter, or Facebooker, the fact that someone *explicitly subscribed to your feed* does not mean that they will, in fact, see your feed.
The platforms treat your unambiguous request to receive messages from others as mere suggestions, a "signal" to be mixed into other signals in the #ContentModeration algorithm that orders your feed, mixing in items from strangers whose material you never asked to see.
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