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Mastodon's official stance on Threads
(blog.joinmastodon.org)
This is a most excellent place for technology news and articles.
That era was still too early for widespread self-hosting and people were barely discovering all that internet tech. So what Jabber/XMPP offered was still neither appealing nor user-friendly enough.
Moreover, it was Whatsapp that fixed your mobile number as your username that ruined Jabber's momentum, not Google. Google Talk or Chat had never reached a notable market share.