Well in my case it's perfectly clear that the problem was defederation because the comments I was able to see with my feddit instance were all there precisely up to the point where a person from lemmy.fmhy.ml, an instance that is blocked on feddit, posted something and everything that was in context of that post was gone when viewed from feddit.
Taxxor
I feel you. When creating an UI you can think of thousands of possibilities which might not be clear to someone however obvious they seem and then design it in a way that couldn't possibly be misunderstood, then show it to different people who all agree that it's clearly structured and logical..... and the minute you release it you get posts from users where you ask yourself how they could even exist on their own.
But that only helps in knowing which communities I can see, I still don't know how much I'm missing out in the comments on other communities because some of them might be from people my instance has defederated.
I noticed this today when I had a comment chain on lemmy.world that I accessed with my lemm.ee instance. That chain was >10 posts long with several different users from different instances.
When I looked into that community with my feddit.de account, I could only see the first two comments of that chain, not even my own lemm.ee comments were visible despite not being blocked by feddit.de.
It was because the third post of that chain was made by a user on an instance that is blocked by feddit.de and that lead to all following posts also missing.
So now I’m feeling like I’m possibly missing big parts of all those comment sections just because they happen to include a comment from a user of a blocked instance somewhere early in the chain.
Reddit isn’t totally free of this problem (feature) either–You can have multiple subreddits dedicated to the same topic.
True, but there you don't have the problem that you can't access subreddit "gamingA" because you happen to be logged in on "gamingB" and those two defederated. You can just access all of the different subreddits with one account and freely choose on which on you'd like to post and always able to see every post ever made in every sub
I don't use many extensions, but apart from the usual UBlock Origin I'll say something exotic: UltraWideo
Because sites like disney+ still don't know that 21:9 monitors exist so you have to force it to scale their 21:9 films to your monitor instead of giving you black bars on all sides