The success of mobile text messaging poses many questions for usability studies. Considering the inherent usability weaknesses of mobile phones such as the small display, poor input methods, the moving environment, and noisy surroundings, this success is hard to explain with traditional usability theories that ignore the social-cultural context. A new framework-cultural usability-is proposed for studying the intriguing processes of how cultural factors and contextual issues affect the consumption of mobile text messaging in contexts of use.