Abstract | It is hoped that context-aware systems will present users with an increasing number of relevant services in an increasingly wide range of contexts. With this expansion, numerous service notifications could overwhelm users. Therefore, careful design of the notification mechanism is needed. In this paper, we investigate how semantic richness of different types of audio stimuli can be utilised to shape the intuitiveness of mobile service notifications. In order to do so, we first develop a categorisation of mobile services so that clustered services can share the same notifications. Not surprisingly, it was found that overall speech performed better than non-speech sounds, and auditory icons performed overall better than earcons. However, exceptions were observed when richer semantics were utilised in the seemingly poorer medium. We argue that success and subjective preference of auditory mobile service notifications heavily depends on the success and level of directness of the metaphors used.