"At the heart of Matrix protocol, you have a kind of merging algorithm that reminds a bit of Google Wave. It means that a conversation is conceptually represented as a sort document you constantly merge on the server. This is a consuming process that is happening on the server for each message received in all conversations. That’s why Matrix has the reputation to be so difficult to scale."
#MickaëlRémond, @ejabberd, 2022
https://www.process-one.net/blog/matrix-protocol-added-to-ejabberd/
Fair comment @matrix?