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.
I was contemplating signing up on that instance but couldn't find anything about who runs it, or how likely it was to stick around. I think there was also a thread on there where they refused to accept donations too.
With an average VPS running you about 100-200 quid a year, as a hobby I think it's gonna get expensive when you need to upgrade cores, storage etc. Not to mention you also need to moderate the instance.
For hosting a federated Lemmy to work I think you need a team and possibly a plan for accepting donations if it can't be run out of pocket
I wish I'd noted the user name of the server owner, I think they were on mastodon.