Small instance with about 3 users and myself online for about 2 weeks.

pictrs   930M
postgres 1.4G

I run lemmyverse.org.

No, communities on different instances will not have the same content. This is one of the features of the fediverse.

Each instance can have it’s own /c/memes and they won’t conflict. So, there could be https://lemmy.world/c/memes and https://lemmyverse.org/c/memes and they could each be different with different content and rules. If you want to see each instances ‘memes’ community, then you will need to subscribe to them individually from your home instance. Once you do that, the ‘memes’ community will be ‘cached’ on your home instance and it will show up in everyone’s feed on your home server.

Absolutely.

As someone who owns their own instance, it is hard to get your instance recognized. You don’t have much content because of the lack of people, and it’s hard to get content if you don’t have people join. It’s a chicken and the egg scenario. Because of this some people choose to re-post content from Reddit to attract people over to their instance. It’s great to see the Lemmy community grow, but everyone joining a few huge Lemmy servers kind of defeats the purpose of the fediverse.

I dont have much to add other than I am an experienced admin and was dismayed at how vulnerable Lemmy is. Having an option to have open registrations with no checks is not great. No serious platform would allow that.

I dont know of a bulletproof way to weed put the bad actors, but a voting system that Lemmy can leverage, with a minimum reputation in order to stay federated might work. This would require some changes that I’m not sure the devs can or would make. Without any protection in place, people will get frustrated and abandon Lemmy. I would.