From the website:
"Mobile crowdsourcing seeks to leverage millions of users with mobile phones, particularly smartphones, to obtain valuable sensor data for application domains ranging from citizen science to transportation and healthcare.
mCrowd is a system that enables mobile crowdsourcing by providing a marketplace for micro-sensing tasks that can be performed from your mobile phone. As a requester of data, you can easily create tasks that uses the general public to capture geo-tagged images, audio snippets, or fill out surveys. As a submitter of data, you can download our app from the AppStore and contribute to efforts including citizen science, volunteer journalism, and others. mCrowd offers several features including location-based tasks, and REST APIs for easy integration with third-party sites."