A lot of people join on a big instance (like mastodon.social, which is the biggest). It doesn't matter as much, as long it's not an extreme-left/right oriented instance, because those end up blocking or being blocked by other instances. You can follow anyone on any mastodon server that is not blocked by/from yours.
If you basically want to have niche discussions, joining a niche instance might be the way (like urusai.social for anime). If not, I personally prefer just going with a big instance. I'm just moving back to mastodon.social for my main profile, and there are 2 reasons:
- Searching for content: if you are on a small instance that doesn't federate with a lot of instances, searching will not return any posts/users from those.
- Reading replies to other's posts: This is where it's a bit weird, and they don't yet developed a solution. If I post something on instance A, and you are on instance B that federated with it, you see my post. But if a person from instance C (that federates with A but not yet with B) replies to my post, you won't see their replies. This lead to some people being like: "is that why a bunch of people on different instances reply the exact same thing, as if it wasn't already said in the replies?"
Then you look at the federated feed (all messages that are sent to your instance) and follow anyone who posts anything remotely interesting.
Once your feed is too quick to follow, unfollow anyone posting any message you feel is uninteresting until the feed slows down.
At this point you should have a pretty nice starting point.
That's how I started in 2017 and I'm still there so I must have done something right at least.
I appreciate the thoughtful response!
Edit: I do love mindly.social for a more laid back/be nice overall sentiment. Although this week I decided to move back to mastodon.social because of the comments/replies thing I mentioned in my other comment here
I went for fosstodon.org, as I think this suits my interests well enough, but there are other general or broad topic instances out there.
And the second thing is the type of instances that are blocking mastodon.social: based on what I usually see going on on mastodon and lemmy, they are probably instances focusing heavily of LGBTQ+ or other marginalized communities. So unless that's the most important thing to you, you won't miss it.
quick note: those communities can be REALLY annoying sometimes. I remember seeing people mentioned that they got jumped in because they posted food pics without content warning, in an instance about.... food and cooking. So, if instances like this are blocking mastodon.social... go ahead
Adding an 'originally-posted' field to exports, and allowing mass-posting on the target should technically work, and non-technically be a tricky problem.
The Mastodon API (currently the defacto API for Fedi clients) has no support for backdated posts (see [1]) and servers will push out any status you create to your followers which would mean a deluge of previously seen content. Backdating and a flag for "do not push out backdated posts" could be added[2] but there's a whole raft of problems that come along with it (resource usage for large accounts, who can use the functionality, how do you stop abuse, etc.)
[1] https://docs.joinmastodon.org/methods/statuses/#create
[2] I fudged this into my Akkoma instance to let me backfill history from a Twitter bot.