I’m pretty sure you can create your own bootstrap theme. If someone makes an old.reddit theme for Lemmy I’ll add it to my instance.

PSA: you can choose your default theme in your profile settings. I’m pretty sure the themes available are determined by your home instance’s options

When you say “go down” do you mean what happens if an instance shuts down its servers for good? I think the answer to that is not a technical one. If a sever is owned by an organization (not-for-profit) and it pays it’s cloud provider bills, it’ll stay up forever.

If you mean what happens if there’s a technical issue and the server data is lost, that’s a different and solved issue. Create database backups. Easy peasy.

IMO, I’m not convinced that your proposed algorithm addresses the discoverability issue and we may need a broader set of functionality to make communities (and posts in those communities) more discoverable. Additionally, consider that you’re idea for this algorithm is wrong, and someone comes up with a better (more performant and/or effective) one or one with a completely different set of goals in mind. What would we do then?

I wonder if there is a need to bake this functionality directly into the source code for the lemmy-ui or lemmy backend. Perhaps a better approach would be to allow instances to implement their own sorting algorithms and the lemmy-ui/backend just add the API necessary to do so.

This is an RFC, OP’s asking for opinions/gauging interest in the work, presumably before the work begins.