Reddit has the users to sustain multiple communities. On Lemmy, it turns what could be a community into a bunch of individual people screaming into the void alone.

This is nitpicky, but the story of target predicting a pregnancy was very overhyped; see: https://medium.com/@colin.fraser/target-didnt-figure-out-a-teen-girl-was-pregnant-before-her-father-did-a6be13b973a5