A place where merchants come together in order to sell their goods and services to a broad audience. Online marketplaces usually provide merchants with much of the “plumbing” that’s needed in order to facilitate online sales (payment processing, shipping providers, the infrastructure for hosting the site, etc.). Merchants are responsible for listing/managing their catalog, fulfilling orders and handling customer service requests (although some marketplaces will “front” customer requests on behalf of merchants). Marketplaces exist for B2C (i.e. Amazon) and B2B (Amazon, Alibaba).