In contrast to the high overhead of Webvan, which had its own refrigerated warehouses and a fleet of trucks, Instacart is built on a crowdsourcing model. Its 10 full-time employees, mostly engineers, work from a small office in San Francisco’s South Park neighborhood. Its app sends customer orders to about 200 independent Bay Area personal shoppers, who receive commissions based on the number of items and orders they deliver in their own vehicles. The app features detailed maps of local supermarkets and can direct the personal shoppers to specific aisles. Founder Apoorva Mehta says Instacart’s “secret sauce” is its fulfillment software, which allows the online retailer to combine orders placed at different times and fill them from different stores—supplementing frozen food from Trader Joe’s with fresh fruit from Whole Foods and cereal from Costco. Customers assemble their orders with lengthy drop-down menus on Instacart’s website or app.