One limitation of the MHT studies to-date has been the platform-specific nature of the MHT systems used: rather than using platform-independent software, the systems deployed to date have been custom-created for specific cell-phone platforms (e.g., the Kyocera pdQ 1900, the Palm Treo family of SmartPhones, or the Motorola QA30). As a result, until now, MHT has been limited use by participants in research studies who were provided with a research-funded cell phone.