Sure. I noticed that many people come from the angle that decentralization implies defi, because they've seen the last few years of decentralization practically

Sure. I noticed that many people come from the angle that decentralization implies defi, because they've seen the last few years of decentralization practically be synonymous with blockchains. I'm just responding to that, and saying that there's lots of interesting applications possible in the decentralized space that don't involve blockchains or finance. Blockchains are just a global append-only stack of messages with global consensus. Mastodon isn't decentralized so I didn't intend to compare them at all. That said, I think federated systems are interesting and have a place, because full decentralization is often impractical.