Ever increasing efforts are spent in developing techniques and tools for a full exploitation of semantics in mobile environments, able to overcome volatility and resource limitations of mobile contexts. This paper presents a platform-independent mobile semantic discovery framework as well as a working prototypical implementation which enables advanced knowledge-based services taking into account user's location. The proposed approach is clarified and motivated in a ubiquitous tourism case study, where some evaluations are presented to prove its feasibility and usefulness.