Neighbourly sharing usually fails for two unglamorous reasons: nobody wants to be the one who knocks on a door first, and nobody knows who has what. This builds the sheet and writes the awkward messages for you. Everything stays in your browser — print the sheet or screenshot it into a group chat.
A street WhatsApp group goes quiet because asking in public risks being turned down in public. A printed sheet on a noticeboard, or a message sent to one person, has no audience. It also fixes the timing problem: offers written down can be claimed on Tuesday for something needed on Saturday.
Two ground rules that keep it going. First, keep it small — a dozen houses beats a hundred, because people need to recognise each other's names. Second, never let it become a debt ledger. The moment someone keeps score, sharing stops.