why ysk: especially if you’re a new user it will help you understand the different projects, their goals, and how the projects interact with each other. It’s really easy to understand and an excellent starter guide to the fediverse. Check it out here
I can try to answer some if not all your questions to the best of my knowledge as someone who also got more into the Fediverse more recently.
When you mean follow a topic, do you mean like how on Reddit you just follow a subreddit? On what you would call a subbreddit is what on Kbin are called Magazines and is how you follow a topic. I’m not sure if that answers your question though.
Federating and De-federating is in regards to Instances/servers closing themselves off to other instances/servers. An example of this currently is Beehaw.org closing itself off to lemmy.world and sh.itjust.works. What this means is if you are for example a user who account is on lemmy.world and try to look at a community on beehaw.org like !technology.beehaw.org, you will see the community and its post but you’ll only be looking at old cached posts from before the de-federation between the instances/servers happened. This same thing goes for Beehaw because de-federating goes both ways.
There is nothing wrong with having multiple accounts across different platforms but instances might be a little much unless you’re in an instance who is de-federated from an instance you want to interact with. But of course that’s all down to choice.
This is something that a lot of people want but currently is not possible. Hopefully in the future something like that is possible but for now the only you can do (which is something I do with different fediverse platforms) is link in your bios the different places you have accounts. Not everybody looks at peoples accounts though but its a start.
It can be yes if thats what you prefer. I personally like consuming the content on their respective platforms i.e posts from Mastodon on Mastodon, posts on Kbin on Kbin, etc because I prefer using them with their own U.I’s. But if you prefer to keeps central on one account you can very do that because thats the power of the fediverse/ActivityPub.
I hope I didn’t ramble on too much and its readable/understandably to read. I’m not an expert or super knowledgeable person on fediverse stuff but I try.