#ActivityPub is super cool once you see it in action.
For instance, you can visit the new StarTrek lemmy server here: https://startrek.website/c/startrek. Looks like a reddit sub with posts, threaded comments, upvotes, &c.
OR you can follow the same server on Mastodon @startrek.
Every thread and comment shows up as a boosted post.
Cool, right? Now, say you find a comment that you want to reply to. Post through your favorite Mastodon app, and that feeds right back to the thread on the #Lemmy server! 🤯
They’re probably unrelated communities that happened to choose the same name, especially if it’s something generic like “politics” or whatever. Best to assume there’s no affiliation unless they specifically say otherwise.
Yeah they DEFINITELY aren’t the same communities. For lemmy and kbin instances (the two reddit-like softwares on the fediverse) communities are like subreddits but they are subreddits specific to that particular website/instance (startrek.website, lemmy.wordl). Many different lemmy instances/websites (and kbin instances/websites for that matter too) can have their own /c/politics, they are entirely separate entities that just happen to share a name.
A bit confusing, not gonna lie lol, but I think it ultimately makes sense as a way to structure things.
Also kbin calls subreddits “magazines” and an example of a subreddit on a kbin instance is https://kbin.social/m/gaming