The whole conundrum of “choosing an instance” is a phase that early adopters like us go through. People can’t be expected to go through the choosing part, then find communities to follow.
We expect people to find their specific instances without even knowing what Lemmy is and if needed, grow their fediverse presence from there.
This decentralised nature is the fundamental idea of fediverse. More generalised communities like lemmy.world means we keep trying to build a centralised alternative to Reddit.
The ultimate end user doesn’t even need to know what Lemmy is. Much like a blog’s reader doesn’t have to know what Wordpress is. They can create an account at arsenal.club and if needed also subscribe to [email protected]. But by default they see their local feed filled with news related to Arsenal. And their subscribed feed full of their interests apart from Arsenal.
The local feed is what differentiates an instance. The quality of which is a direct indicator of the instance’s quality. Hence the most important feed
To answer the last part of your question, they don’t need to think of Lemmy at all. “Lemmy” is a framework, not a social network. infosec.pub is the social network I’m on. I don’t need to know about Lemmy at all (most of us don’t know what powers Reddit). Here we discuss information security and I can also communicate with the wider fediverse.
It doesn’t even have to be lemmy. I can connect to anything that uses activitypub. Mastodon, Kbin, Bookwyrm, Wordpress, etc. using my infosec.pub account.
The lemmy code provided by lemmy team is cloned and then patched (if needed) by infosec.pub maintainers and then deployed to their servers. The code for all intent and purpose is owned and maintained by infosec.pub. Lemmy doesn’t have any real control at that point.
Same with the arsenal example. arsenal.club is a social network about Arsenal powered by lemmy framework. If mufc.club uses another activitypub enabled protocol, the arsenal fan on arsenal.club can view that in their subscribed feed too.