The reputation-oriented trust issue is critical to e-commerce applications and has drawn much attention from both industry and the research community. Some e-commerce systems have introduced trust management mechanisms that leave some valuable information to customers. However, more comprehensive mechanisms should be provided to more precisely depict the trust level of sellers and forthcoming transactions, and the relationship between interacting entities. Here, the authors review the reputation-based trust evaluation mechanisms in literature and outline some trust issues that are particularly important in e-commerce environments.Keywords: trust computing, e-commerce, trust evaluation, reputation E-commerce has been a popular and growing industry in which buyers and sellers conduct transactions on the Web. Numerous e-commerce companies have created very profitable businesses since pioneering e-commerce traders (such as Amazon.com) or e-commerce Web sites (such as eBay.com) emerged more than 10 years ago.Recently, service-oriented computing (SOC) has emerged as an important technology that has received attention from both the research community and service industry. Using SOC, a spectrum of e-services across server domains might be available to customers in a loosely coupled manner. Customers can look for qualified and preferred services via a registry's discovery capability, invoke one or more of the services in an integrated way, and receive their desired outcome from selected services. Services in SOC might result in a business transaction, such as selling a product online, or a functional execution of a specific Web service, such as responding to a query on a stock quote. Thus, in an SOC context, the notion of service encompasses most e-commerce applications.In both e-commerce and e-service applications, a seller's reputation is a big concern for buyers prior to placing an order or making a payment. In the abstract sense, trust is the extent that one party measures the other party is willing and able to act in the measuring party's interest. 1 It's also the probability by which party A expects that another party B will perform a given action. When a customer looks for a service from a large set of candidates or service providers, the promised quality and the trust placed on that promise are key factors to the customer making the service selections. These factors are also critical for service registries, which are responsible for maintaining recommended lists of reputable and trustworthy services and service suppliers.An e-commerce support environment can produce the trust value by measuring the delivered service quality as well as service evaluations from customers and trust management authorities. Without any trust-management mechanism, many customers might invoke fraudulent services with deceptive advertisements. On the other hand, a simple but incompetent trust management system could let service providers selectively victimize customers (for example, by providing good services with low-cost transactions b...