The site had a ritual: a monthly “Exchange Night.” For one evening, the homepage would dissolve into a virtual commons — a map of live streams, a mosaic of faces, a queue where people uploaded the thing they wanted to give away. It was less about streaming polished talks than the messy business of sharing: a single mother in a suburb offering a bag of winter coats; a teacher offering lesson plans; an artist offering to teach a class in how to make pigments from urban dust. The event was noisy and kind and often chaotic; it could also be life-changing. People met mentors, found lost relatives, swapped tools, or learned to mend a beloved coat whose lining once held a child’s drawing.