But it's hardly a fair comparison, especially because it seems I cannot upload SVG files to Mbin. I also didn't make the lines thinner or any other adjustments that might be a good idea at this scale. Still, might be better than noting.
"probably" is a nice word here. I have seen no indication that Mastodon plans to make their groups difficult to work with for other platforms. There is, however, many interests to take into account to ensure a good user experience, and not one solution is guaranteed to work well for everyone. What works in the Threadiverse might very well be terrible in Mastodon. They follow very different network dynamics.
Lemmy does not, as of now, interoperate very well with Fediverse services such as Mastodon and Pixelfed. Sure, you can follow Lemmy communities from Mastodon, but it's not a pleasant experience. The group just boosts everything that is ever posted to it.
Likewise, Lemmy does not work with Phanphy - it has its own API, and separate apps. It's too different from Pixelfed/Mastodon for it to make sense to share an API.
If you search for @elena@lemmy.world at mastodon.social you will, however, be able to see your user from there; you can view this post, and if you have an account you can comment on it and contribute to the discussion like anyone else. You can also boost the post or comments to it, making it possible for content from Lemmy to reach far and wide. We sometimes do get comments from Mastodon users, so it clear that this happens every now and then, but mostly it's kept separate.
Mastodon users can also post to Lemmy by tagging a community (like they would tag an a.gup.pe group), but it's not very intuitive.
We commonly refer to Lemmy as part of the Threadiverse - a subset of the Fediverse which revolves around threaded discussions around shared content (Reddit like). The main platforms are Lemmy, Mbin (which is what I'm currently posting from), and PieFed.
Mbin and PieFed go further in the direction of interoperability than Lemmy does. Mbin supports Mastodon-like microblogging; if you check out the search for the hashtag Lemmy, you'll see not only this post, but also microblogs from Mastodon and all kinds of content. Limited, of course, by what is federated with that instance (Kbin.earth doesn't have too many users).
In Piefed, users can follow Mastodon groups made with a.gup.pe, such as the knitting group. Often Mastodon users start their posts by tagging each other, so it doesn't look completely native, but it can be neat. You can also follow PeerTube channels directly in Piefed.
In short, it's quite complicated - there are different platforms, and they all solve interoperability differently and prioritize it to different degrees. There's always the possibility that Mastodon users will stop by and say hello, but how easy it is made for them to do so varies quite a lot.
I had a bit of a slow start on Mastodon, but after sticking with it for a while it's now by far the best social media experience I've ever had. I follow less than 200 people, not all of them active, but their posts along with the content they boost provides a much more interesting feed for me than any algorithm ever has.
And when I post something I've put work into, it's boosted by those interested and reaches far more relevant people than I've ever reached on other networks. And people trust it to be interesting because it's boosted by someone they trust, rather than some faceless algorithm.
That said, the cost of entry is indeed a bit high.
Ah yeah, it's not possible on Mastodon either. Your content stays where it is.
I think it's even less of a problem on the Threadiverse than it is on Mastodon though. Most people are interested in new content here, we rarely go digging too much through the archives. Though it would of course be neat.
On Mastodon it's all about who you're following and who you're being followed by, so being able to move somewhere else and take your followers with you is a big deal.
On the Threadiverse we don't really follow users so much, so the whole concept of account migration becomes very different. Migration of communities rather than of users would probably be the best parallel - it would be great if subscribers could automatically follow a migrating community without having to manually resubscribe.
I guess it's also natural that subcultures that tend to be banned elsewhere are early adaptors of alternative platforms.
We're lucky we didn't exist when the Trump extremists on Reddit went looking for a new home, or they would probably have been one of the biggest fields in this figure. Hopefully when the right wing extremists arrive instance admins will have the good sense to defederate.
What we're interested in is not the number of users, but the trends: whether the number is increasing or decreasing over time. Starting the axis at 0 would not be useful in this regard, as the trend would be almost completely obscured.
And in white, for the dark mode folks:
⁂
But it's hardly a fair comparison, especially because it seems I cannot upload SVG files to Mbin. I also didn't make the lines thinner or any other adjustments that might be a good idea at this scale. Still, might be better than noting.