On My profile, check I’ll greet people who just joined. You get an in-app alert (and lock-screen push if you turned that on) when someone signs up. Home shows a Welcome wagon list of newest faces in your age group (hosts can greet either). Say hello on their profile or in Introductions — not a street, not a cold DM across 13–17 and 18+. Uncheck anytime.
Welcome wagon
Opt in to greet people who just joined — you get an alert on each new signup.