I actually don’t remember what taught me about Lemmy and Kbin’s existence.
For me it was a german podcast about social media called "Haken dran". For a short time, they had a community on feddit.de, where the hosts also occassionally visited and sometimes they would mention "feddit" in their podcast, which got me on the hook.
Sadly, the podcast by now moved its community to discord.
Anyways, I do think metions in podcasts, YouTube videos, etc., matter. It raises awareness beyond the big companies fucking things up ... though I think the most effective thing to grow the Fediverse is to code better software.
Piefed solves this with topics kind of neatly. You keep the unique communities but they are all in one place