Smartphones "don't keep secrets," say Scott Thurm and Yukari Iwatani Kane in The Wall Street Journal. In a detailed investigation of 101 iPhone and Android apps, the reporters found that, unbeknownst to users, dozens of popular applications transmit personal information from your phone to advertising firms and other companies, including "phone numbers, current location, often the owner's real name—even a unique ID number that can never be changed or turned off." Is there a way to stem the flow of sensitive data? Here's a brief guide to the findings.

How many apps send private information?
Out of 101 apps tested, 56 "transmitted the phone's unique device ID to other companies without users' awareness or consent," and 47 transmitted the phone's location. Another five sent age and gender details to companies.

Which were the worst offenders?
TextPlus 4, a popular text-messaging app for the iPhone," sent the phone's unique ID number to eight ad companies and the phone's zip code, along with the user's age and gender, to two of them." Pandora, the popular music-streaming app, sent age, gender, and location details to third-party ad companies. In this limited test, iPhone apps proved more problematic than Android options, but "it's not known if the pattern holds among the hundreds of thousands of apps available."

What's Apple's position on this?
Apple says it reviews each app before approving it for download, and a company representative says that "we have created strong privacy protections for our customers, especially regarding location-based data." But the WSJ found that app developers can easily skirt restrictions — and Catalin Alexandru at TFTS says that Apple's assurance basically means "nothing." The company "won’t even tell if it has rules against this sort of thing."

Why aren't companies doing more to protect users' privacy?
Both Apple and Google have big stakes in mobile advertising. They "run the two biggest services, by revenue, for putting ads on mobile phones." Such personal details have "become core foundations of the mobile ad industry," says Daniel Eran Dilger at Apple Insider, so changing how companies gather them would be difficult.

What can you do to protect yourself?
Smartphone users "are all but powerless to limit the tracking," say The Wall Street Journal's Thurm and Kane. Unlike personal computer users, they can't turn off the tracking software, at least not yet. The only way to be completely safe, says Geoff Herbert at, is to "turn off your smartphone, throw it on the ground," and "jump on it repeatedly." Or just "don't use the apps."

Sources: Wall Street Journal,, Apple Insider, TFTS