E-commerce refers to using the internet to conduct commercial transactions and generate revenue. Popular forms of e-commerce include online retail stores, mobile recharges, ticket and hotel bookings. E-commerce allows commerce to take place anywhere, anytime, with anyone. It involves virtual storefronts, gathering customer demographic data, business-to-business exchanges, email/fax marketing, and providing online services. New forms of e-commerce payment are emerging besides cash transactions, such as bartering goods due to economic uncertainties.