The Nextdoor app is part of an elite group of things (Joe Wicks, Deliveroo, sourdough starters) that have had a “Good Lockdown”, rising from niche interest to national hobby. Although you perhaps wouldn’t know of the neighbourhood app’s success to scroll through its pages where users are still preoccupied posting about the horrors of bike thefts, lost cats and Covid vaccine scams: really, it’s a...