Mastodon Clone by Red Planet Labs
Summary:
Rebuilt the Mastodon backend from scratch and made it able to handle Twitter-scale (500M users, 20M writes/second, unbalanced social graph, etc.). Thus implementation is only 10k lines of code and is also significantly simpler than the existing Mastodon implementation. This clone is running at mastodon.redplanetlabs.com.
Full Article : Read here
Impressive but I hope if an instance ever got to 500M users we would block it. That’s ultimately a terrible thing for fedi