An investigation by the Wall Street Journal has confirmed what many smartphone users have long feared – many of your apps are mining your personal data.  

The study examined the transmissions of 101 Android (Google) and iOS (Apple) apps.  According to the report:

[The results] showed that 56 transmitted the phone's unique device ID to other companies without users' awareness or consent. Forty-seven apps transmitted the phone's location in some way. Five sent age, gender and other personal details to outsider.

A common use of the data was to sell it to advertisers.  "TextPlus 4", a top iOS app, sold the phone's unique ID number to eight ad companies and the user's age and gender, to two of them.  "Paper Toss", the best-selling Android and iOS app, sent the phone's ID to five companies.  And the ever-popular Pandora internet radio app sent the user's age, gender, location and phone IDs to advertisers.

Apple spokesman Tom Neumayr claimed in a comment to the WSJ, "We have created strong privacy protections for our customers, especially regarding location-based data.  Privacy and trust are vitally important."

Despite "strong privacy protections", many app makers are sending location data to advertisers.  And those advertisers, in theory, could pass that information on to whoever they please.  While some apps (like Pandora) require the user to briefly approve sharing their location, other approved apps like the iOS's "Pumpkin Maker" share the information with no request for permission.  The maker of this app claimed ignorance of Apple's policy when contacted by the WSJ.

More troublesome still, some apps -- including Angry Birds and DoodleJump -- were found to be transmitting the user's screen name or password to advertisers -- information that could be used to compromise weakly passworded accounts.

While PC users can block tracking via browser extensions and deleting cookies, smart phone users don't have the same kind of options.  Ultimately the choice at this point appears to be -- accept that some of your information will be sold to advertisers or don't use smart phone apps.