To be successful, e-commerce solutions need to properly address accountability issues. Accountability is fundamental to business, and identity is fundamental to accountability. This paper analyses the role identity services play in supporting business-to- business (B2B) e-commerce. There are many good reasons for outsourcing identity management, and current solutions address some of these such as convenience or access control at the time of a transaction. However, if identity services are to help reduce the risks and track liabilities, then they must also support long- term accountability. By analysing the long-term accountability needs of e-business this paper shows that a trusted identity service must address longevity, confidentiality, simplicity and trustworthiness. This in turn produces new challenges for the technology, architecture and business model of such services. Identity is only one piece needed for accountability. The trust services vision is that the other pieces will be resolved by using similar accountable third party services. 15 Pages