I see you asked this question 4 years ago, now lemmy is absolutely necessary since Reddit died.
I learned about Lemmy on Reddit from people who already knew about it, before the July 1st 2023 snoopocalypse I’m grateful there were plenty of redditors who explained thoroughly to everyone how to get into Lemmy.
It still took me 5 months to successfully join Lemmy because every time I tried to join an instance, they were too full or they didn’t respond or it would just buffer forever. One time it buffered for 24 hours and still no luck. But I finally got into Lemmy November 2023!
Someone mentioned it on Reddit and on Riot -I don’t remember in what subreddit or room- while talking about federated alternatives to Reddit. Came here, saw the Github, lurked a bit. Looks an interesting project and I can’t wait for federation to come!