Comment by marknadal

Mastodon is FEDERATED, not decentralized.

Federated systems, like email, have used these anti-spam techniques for a long time.

Federated systems always evolve into an Oligarchy, like Gmail/Hotmail/Yahoo, etc. or like banks, JPMorganChase/GoldmanSachs/etc.

If you want decentralization, you should more go for something like https://notabug.io/ (P2P Reddit), which uses the GUN protocol (mine). Or any WebTorrent-based approach.