Wouldn’t Mastodon just be that? Lemmy and Mastodon federate - and you can see one in the other.

Twitter-likes are tag based. Reddit-likes are community based? I think it’s fine and good if communities merge or get subsumed by an equivalent on another instance.

I believe the chart is if you are looking at last activity date.

Was this persons’ last activity date in the last 6 months? Last 1 month?

Not sure how they are actually measuring that activity - whether that’s logins or posts?

It is limited, yes, the pixel you place is one amongst many - you are just one part of the much larger project. That’s the fun part

You too, friend. Can you not create communities on other instances? I hadn’t tried or thought about it. I guess that’s a downside of a really small or self hosted instance