A variety of interesting papers in Utrecht for the 13th Meeting of Computers in Urban Modelling and Urban Management (July 3-5, 2013). Harry Timmermans gave an interesting keynote “What-ifs, if-whats and maybes : sketch of ubiquitous collaborative decision support technology” which is printed in the preprinted book of the conference Geertman, S.(ed.): Planning Support Systems for Sustainable Urban Development. Berlin: Springer. Resonates very strongly with my own keynote in Cambridge last week. The notion of long term spatial structure beginning to fade as an organising concept for the city as more and more activities are structured through real time short term responses using mobile devices, was key to his talk.