The trends in web development of educational applications and of Web 2.0 or social applications are converging. Platforms are designed to host a variety of software components (called widgets or plugins), which can be organised or combined (mashed-up) at user’s convenience. Such platforms can be exploited as both personalised learning environment (PLE) and as social network applications. This article argues that six qualitative dimensions can be defined to analyse the main features of these platforms: the screen dimension measures the visual integration, the data dimension measures the portability of data, the temporal dimension measures the rate of data synchronisation, the social dimension measures the networking of users, the activity dimension measures the structuring of users’ interactions with the environment, and the runtime dimension measures the flexibility in accessing the environment from different end points. As a proof of concept of the introduced dimensions, a few familiar Web 2.0 platforms are first measured along each dimension and then, using the results visualised as spider diagrams, compared with respect to their usefulness as PLEs.