Instances that are not trying to attract a new audience might want to turn on the new Private Instance setting, which makes everything private. The home page, posts, communities, etc will all require a login to view. Bots and scrapers won't be able to get anything useful from your instance and will stop trying.
Also if a single-user instance is subscribed to mostly NSFW communities, maybe they don't want everyone to be able to see which communities are listed at /communities.
Or it could be used temporarily when a biiig flood of scrapers turn up, then turn it back off when they go away.
Edit: Federation is unaffected by this. For logged-in users everything continues as before.
Nice!
Does it still federate with that enabled? Last I checked, enabling private instance in Lemmy also disabled federation.
It still federates, yes.
This was changed in Lemmy 0.19.11, now you can have private instance with federation enabled to prevent crawling.
I had coded up something similar (but less configurable) on my own single-user pyfedi instance. But this is really nice. In particular it's surprising that we can now do something that lemmy can't (yet).
I wonder what's next on the radar. Implementing https://github.com/LemmyNet/lemmy/issues/5578 maybe? (Thought I wouldn't be surprised if this was also already implemented...)
Yes, that's done. When you block an instance it is the equivalent of a user-level defederation.