Online to offline, or O2O, is when a purchase path begins online and ends in an offline purchase. Click-and-collect (picking up online purchases in-store instead of having them delivered to home) is an example of an O2O service.
Today, O2O can also refer to the opposite buying experience: offline to online. In this case, in-store services (think in-store tablets) result in an online purchase. China is particularly advanced in terms of O2O commerce, thanks to the widespread popularity of mobile payment. Chinese consumers can use WeChat Pay and Alipay to buy any product or service, including street food snacks.