Abstract
The Web is currently undergoing a change from a document- to a services-centered environment. This shift can be seen as a first step towards a component-centered environment. We shall explore requirements for a Web component architecture based on the Web services framework, which has been promoted recently. A description language, protocols, and repository and directory services are the key elements. We will motivate an underlying conceptual model for these aspects capturing their foundations. We will identify two key features for a Web component framework - a two-layered type system capturing two different behavioural aspects and semantic descriptions of components - that makes it different from a services environment.