With apologies for sounding like a McDonald's ad, I'm loving it!
I was very wary when I switched over the day before the app-pocalypse because of my experience trying to replace twitter with Mastodon, but this place has NOT felt like yelling into the void, it's immediately done most of what I used reddit for!
Incidentally (by coincidence) I registered on Mastodon yesterday evening, and I too felt like I had landed into an empty pit... Not sure why, by default everything is empty, and I tried adding interesting stuff to follow but somehow didn't find anything interesting
I think a big part of it is the kind of sites twitter/Mastodon and reddit/Lemmy are;
The by far biggest selling point of twitter is that you have instant access to hundreds of millions if not billions of people whether you want to or not. Aside from scale, the very fact of federation works against that.
It's kinda the online equivalent of you and all your friends living in the same neighbourhood in a metropolis, but someone decides to dump the whole world's toxic waste there, declaring any attempt to clean it up a gross violation and you flee to each your own tiny village spread over multiple continents.