Lemmy works like Reddit: communities, posts, upvotes, threaded comments. The difference is that it runs on hundreds of independently operated servers that talk to each other. You sign up on one instance, and you can follow communities hosted anywhere on the network. No single company owns the platform, there are no ads, and there is no tracking. Each server sets its own moderation rules, so the experience varies depending on where you register.

The software is open source and lightweight enough to run on a small VPS. If you are tired of corporate social platforms changing the rules, Lemmy offers a model where the community owns the infrastructure. It is not as polished as Reddit, and finding the right instance takes a little effort, but for many users that trade-off is worth it.