Good discovery tools are essential on a federated platform. An important part of twitter, facebook, and reddit success is/was that that they were the place for their particular style of content. You had a pretty good chance of being able to discover your old high school friends, because they were on the one platform. Then the (early) algorithm started discovering for you all the obscure content similar to your history.

Discovery has to work differently in a federated system. You can search for communities on Lemmy, but if your instance doesn’t already have someone subscribed to a community, then you’re not going to find it.