Abstract: Methods, apparatuses and systems facilitating payments over a computer network. The on-line payment system of the present invention can be used to facilitate person-to-person payments, person-to-business payments, and business-to-business payments. In one embodiment, the on-line payment system of the present invention leverages the viral elements of on-line payment systems to market other financial services, such as credit and/or debit card services. Other embodiments provide efficient payment protocols reducing transaction costs and fees associated with such payments. Other embodiments of the invention allow users to transfer funds to other users with a telephone number.