One of the riskiest parts of an e-commerce transaction is the payment process. Several different companies, such as Authorize.net, Google, and Yahoo! checkouts, and others provide robust solutions for this risky process. Pick a provider that services the payment process (or some part thereof, such as credit card validation) and write a short summary of what services are provided and why an ecommerce site owner may want to use the services. Include the risks that are mediated by the service.