The paper explores the application of Web 2.0 technologies in the engineering product development domain. Growing on data collected from a number of industrial development projects, related to several different products in various industry segments, the paper analyses the dichotomy between the prevailing hierarchical structure of CAD/PLM/PDM systems and the emerging principles of the Social Web, e.g. the self-organization of its users. It introduces the concept of Engineering 2.0, intended as a more bottom up and lightweight knowledge sharing approach supporting early stage design decisions within cross-functional product development teams. A set of scenarios related, for instance, to the application of blogs, wikis, forums and tags in the engineering domain are eventually presented, highlighting opportunities, challenges and no-go areas.