This site is currently struggling to handle the amount of new users. I have already upgraded the server, but it will go down regardless if half of Reddit tries to join.
However Lemmy is federated software, meaning you can interact seamlessly with communities on other instances like beehaw.org or lemmy.one. The documentation explains in more detail how this works. Use the instance list to find one where you can register. Then use the Community Browser to find interesting communities. Paste the community url into the search field to follow it.
You can help other Reddit refugees by inviting them to the same Lemmy instance where you joined. This way we can spread the load across many different servers. And users with similar interests will end up together on the same instances. Others on the same instance can also automatically see posts from all the communities that you follow.
Edit: If you moderate a large subreddit, do not link your users directly to lemmy.ml in your announcements. That way the server will only go down sooner.
You might wanna consider temporarily closing sign-up requests on
lemmy.mlsimilarly to howmastodon.socialdid it during its large influx. Making a sign-up request and just receiving an infinite loading icon is a very frustrating experience.Similarly, you want to make it as easy as possible to financially contribute to lemmy, even if it means using proprietary platforms like Patreon.
Overall, the current Reddit API change is probably one of the largest opportunities for lemmy right now, so smoothing over the user experience as fast as possible in the coming days will be of atmost importance if we want lemmy to become a viable Reddit alternative...