Context-aware systems allow users to access services and multimedia data according to their current context (location, identity, preferences). Web 2.0 fosters user contribution and presents the web as an application programming platform where third parties can create new applications (mash-ups) mixing the functionality offered by others. We deem that applying Web 2.0 principles to the development of middleware support for context-aware systems could result into a wider adoption of AmI. This work provides a platform which combines social context-aware annotation of objects and spatial regions with sentient mobile devices enabling multi-modal human to environment interaction in order to enable advanced context-aware data and service discovery, filtering and consumption within both indoor and outdoor environments.