A core component of Android security is the permissions system: When you install an app, it notifies you of what it would like to do, such as gain access to your address book and calendar, or send text messages. You can then decide to proceed or dump the app.
Unfortunately, this system puts a lot of responsibility on you to understand whether permission requests are appropriate. South Korean antivirus vendor AhnLab last year reported that of the 150 top-rated Android apps, 43% requested "excessive permissions," based on the purpose of the app. Explanations ranged from developer laziness to marketers trying to collect more information on users.
Which apps are trustworthy? To help identify what an app is doing vs. what it should be doing, the free Clueful Privacy Advisor from BitDefender will review which apps you have installed, then use a reviews database maintained by BitDefender to assign a privacy score to each app. The goal is to help you spot apps that might be silently leaking your device ID to advertising networks, uploading your contacts to the app developer's server, targeting you with adware, or engaging in other unwanted behavior.