Two things: the data on the instance will be gone.
The posts/comments that were replicated on other instances will stay, but they will be defederated, meaning they will not ever be synced up woth other instances’ replications of these posts/comments. Every instance will just have their own, insular copy.
Do the copies on other instances ever expire and get cleared? Or will they stay indefinitely, without updates?
I see this as a big issue for content going forward. I get that reddit is one single point of failure but I wonder how you can keep knowledge in a static state when most instances lose money and it’s a hobby. What happens when the owner grows tired.
How often do you revisit forum posts you made in 2007? Some content doesn’t need to be preserved
It’s not about visiting a forum post I made in 2007. It’s about visiting a forum post about an obscure issue that someone solved in 2007.
That part won’t change. If your current instance was federated with an obscure community/instance before that community/instance disappeared, then you will still have the content from back then and will be able to find the discussion and solution
