On the one hand, architectural knowledge advances very rapidly, with new types of materials and technological innovations entering the field and multiplying architectural invention. On the other hand, urban experts, architects and engineers often debate publicly uncertain urban knowledge and technologies, risky plans and daring designs, polarising opinion-as witnessed on numerous blogs, citizen forums and architecture websites. This radical transformation in building technologies, in the reliance upon experts and in the expansion of architectural networks could have remained practically invisible were it not for the presence of another phenomenon: the digitalisation of architecture and the availability of enormous Internet databases. The digital technologies at our command provide us with abundant resources to follow architectural controversies. © 2012 Cambridge University Press.