In this paper we reinforce the benefits of a trust based approach in mobile multi-agent systems. Whilst we do not specify a trust model we provide a framework for property based trust, defining the observations which underpin many pre-existing trust models. This framework maintains subjectivity which should be the basis of any trust based system yet enables entities to communicate and collaborate trust information regardless of the trust model used for deliberation. We also introduce ‘Trust Communities’ as a representation of property based trust information thus enabling the collaboration of reputation information.