The increase in monthly is just mainly replacing users leaving as the active 6 month seems to be going down the same rate as active monthly is going up. Am I reading that correctly?

Yeah. But the active 6 month is a lagging indicator because it tracks users who became inactive 6 months ago. While the increase in monthly active users is tracking users joining right now. If the increase of monthly active users is sustained for a few months, it'll reverse the 6 month trend as well.

Totally agree that it's ultimately about activity, but the reality is that we need more users to have more activity. I always took for granted the sheer scale of reddit until I joined Lemmy. It takes a massive number of people to sustain continuous 24/7 discussion about a wide variety of topics, which is ultimately what this kind of link aggregator/forum strives to do. And Lemmy users are already really active compared to redditors. There just aren't enough of us yet.

One works like a forum, the other is a microblogging platform. Definitely not the same userbase.

Mastodon is much older as a software. Lemmy is still under active development, we aren't even on version 1 yet

I would just guess it's because the Twitter-like format is more popular but that's because I forgot Threads was even a thing.

Hey, there's a lot of non tankies arguing with each other too.

You fool.

It will if Lemmy becomes successful. It will have to stay tiny and very niche. Or else all communities have to deal with Eternal September if they start getting a lot of users. Then communities will gravitate towards the same lowest common denominator content and comments seen elsewhere.