After developing and using TaintDroid, several universities found that of 30 popular free Android apps, half were sharing GPS data and phone numbers with advertisers and remote servers. A few months ago, one app was sending phone numbers to a remote server in China but today the situation looks a lot more pervasive. In their paper (PDF), the researchers blasted Google saying 'Android's coarse grained access control provides insufficient protection against third-party applications seeking to collect sensitive data.' Google's response: 'Android has taken steps to inform users of this trust relationship and to limit the amount of trust a user must grant to any given application developer. We also provide developers with best practices about how to handle user data. We consistently advise users to only install apps they trust.'