(2/2)
Those of us who've been here since GNU social was the dominant software, remember him shoehorning DMs into OStatus so Mastodon would be more like Titter. Without even making sure they wouldn't display publicly in other software. Spoilers: they did.
So the other projects had to scramble to reverse engineer Mastodon's posting scopes to avoid that. As did AP editors. Even though it would have been better to hold off on DMs, and work towards a protocol-level consensus on doing them right.