Some time ago I proposed one simple thing enhancing retention. Frontends could introduce addition button/link in bio/profile leading to introduction post. That would be more of a suggestion for newbies for the smooth beginning, a lot of newcomers simply don't know how to start. If you are not there from firend's refferal, how can you know there is this culture of introducing yourself on Hive? That thing alone would make it much easier to "catch" these new guys and gals and welcome they warmly.
RE: The Single Most Impactful Thing You Can Do For Hive: Upvote a Newbie