The Semantic Web Education and Outreach (SWEO) Interest Group has published an Interest Group Note Cool URIs for the Semantic Web. The Resource Description Framework (RDF) allows users to describe both Web documents and concepts from the real world people, organizations, topics, things in a computer-processable way. Publishing such descriptions on the Web creates the Semantic Web. URIs (Uniform Resource Identifiers) are very important to the Semantic Web, providing both the core of the framework itself and the link between RDF and the Web. This document presents guidelines for the effective use of URIs in the context of the Semantic Web.