The diffuse Web is an alternative way of using the Web 2.0 infrastructure for building personal diffuse applications. Systems that let users tune the temperature of their house with a cell-phone, check that the shutters are closed with a PDA, or select the music to be played on a Hi-Fi system with a PC are examples of the targeted applications. Diffuse Web applications have similarities with Web 2.0 applications: i) they rely on fast bi-directional interactions between servers and clients, and ii) they make extensive use of non-cachable dynamic contents. On the other hand, diffuse applications have also an important difference with respect to traditional Web applications: they generally do not need to deal with a huge number of simultaneous users. That is, diffuse Web applications are built on top of standard technologies but they use it differently. Therefore they demand different optimizations and tunings. Hop (http://hop.inria.fr) is a platform designed for building and running diff...