The sorting algorithm still needs some tweaking, so it won’t show that many posts from big communities, but spread it out more, so smaller communities also show up.
I actually had to temporarily block the memes community because of this. Sorting by hot resulted in nothing but memes, and it was driving me crazy that they were doing the whole "post old memes" thing.
There was a bug with the hot sort a couple weeks ago, so that kind of poisoned the well a little bit. I'm never sure if the poor sorting is due to another bug or if it's just the nature of how hot and active sort works. Assuming the sorts are working as intended, I'm beginning to believe that lemmy is just too small for hot and active to work well. Maybe they'll be more applicable if lemmy grows to the size of reddit.
But anyway, I've just been sticking to the "top" sorts, for now. Those work well.