We note that over the past decade publish-subscribe systems have improved the ability of users to exchange information but we argue that these systems have been either restrictive or simplistic - relying on narrowly defined channels for data exchange. The Information Dissemination (INFOD) approach we present here introduces a flexible and dynamic framework for brokering information in publish-subscribe systems. INFOD enables communities of interest to constitute and use vocabularies to describe their interests as well as their capabilities (available information). Publishers, consumers and subscribers are real-world entities characterized in terms of vocabularies and constraints within an INFOD registry. Subscribers define subscriptions expressing events of interest at candidate publishers and constraints on the run-time event data. The registry matches entities based on subscriptions and constraints, and sets up event channels between them.