What is Lemmy?
Lemmy is a social media network that works just like Reddit - but is decentralised.
Reddit is a proprietary closed source platform that strictly enforces how you interface with said platform and ls owned by a publicly traded corporation who are currently trying to speedrun the enshitification (or monetization) of their platform in order to increase shareholder value.
Lemmy is an open source project that lets everyday people run and control their own platforms on servers across the globe, who connect with each other to share users and content through the ActivityPub and ActivityStream protocols, which are public web standards recommended by the World Wide Web Consortium (W3C).
The big difference being that major proprietary social platforms run by multinationals have a tendency to monopolize, control, exploit and otherwise abuse their users, where as Lemmy let's pretty much anyone be a vendor of a social media platform - which doesn't eliminate abusive platform holders, moderators or users - but you can block any of these if you'd like, in effect giving you control over what ends up in your feed and how you access that feed, since it's all done through a public protocol and not some proprietary client or API.
Other than that, all social media platforms are information sources, disinformation sources, entertainment hubs and voids we scream into in the hopes that somebody hears us. They are a mirror, a megaphone, a vice and a boon.
But it's better to use a social media platform run by everyday people rather than the goddamn Epstein class. Tell your friends; make your own social media by switching to the Social Web (also known as the "Fediverse") in order to force Reddit, Twitter, Facebook and Threads into obsolescence - shareholders be damned.