Mastodon is pretty active and usable. Patchwork has some big advantages. It's fully distributed, not federated like Mastodon/diaspora/OStatus, and works offli

Mastodon is pretty active and usable. Patchwork has some big advantages. It's fully distributed, not federated like Mastodon/diaspora/OStatus, and works offline. But the experience isn't as polished yet. There are still some lingering issues with Patchwork... namely, it only runs on desktop computers, and your identity is tied to one device. But they are actively working on these issues. Both are really cool and worth checking out.