So I'm actually against this idea. For some communities, the subject is the important thing. But for others, they're competing and they have different standards. Take memes for example. There's a memes community on every instance. Why would Star Trek memes be grouped with Solar Punk memes?

What I would say, is that some people are still stuck on the idea of karma and so they're desperately trying to spam their posts in every relevant community like clout matters. What they'll eventually realise is that they're just spreading their engagement and failing to support any of the moderators.