Since a number of years agent technology is considered one of the most innovative technologies for the development of distributed software systems. While not yet a mainstream approach in software engineering at large, a lot of work on agent technology has been done, many research results and applications have been presented, and some software products exists which have moved from the research community to the industrial community. One of these is JADE, a software framework that facilitates development of interoperable intelligent multi-agent systems and that is distributed under an Open Source License. JADE is a very mature product, used by a heterogeneous community of users both in research activities and in industrial applications. This paper presents JADE and its technological components together with a discussion of the possible reasons for its success and lessons learned from the somewhat detached perspective possible nine years after its inception.