Basically think of discord servers that host subreddits. Instead of r/, the new r/ includes the domain name, kinda like a discord server. The new r/ is !subredditName@ServerName

So if you wanted to search for say, r/furry, you’d type !furry@pawb.social.

Furry is the subreddit, pawb.social is where it is hosted. Over time lemmy will improve and servers will coalesce subreddits like planets around newly formed stars.