While you sleep, your iPhone is probably transmitting private information about you to companies all over the world - including your location and your email address.
That’s the alarming conclusion of a Washington Post investigation, which found that 5,400 ‘app trackers’ in popular apps such as Spotify transmit data to companies.
Data transmitted includes people’s names, email addresses, precise location and phone numbers, according to the survey of popular iOS apps.
The Post investigation used monitoring software to find out what data phones were transmitting and when.
The researchers found that the apps commonly beam information back to companies (or other third parties) in the middle of the night, while owners are asleep.
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Patrick Jackson, chief technology officer for privacy firm Disconnect told the Washington Post, ‘'This is your data. Why should it even leave your phone? Why should it be collected by someone when you don’t know what they’re going to do with it?' told the Post.
'I know the value of data, and I don’t want mine in any hands where it doesn’t need to be.'
A previous investigation found that Facebook hoovers up data from most Android apps - even if users are not logged in to Facebook, or don’t have an account.
Privacy International tested 34 popular Android apps and found that two-thirds send data to Facebook as soon as they are launched.
It makes no difference if people are logged out of Facebook, or don’t have an account.
The data transmitted is used to build up advertising profiles, Privacy International said - but could build up detailed information on private matters such as health or religion, the privacy group said.
Privacy International said, ‘We found that at least 61 percent of apps we tested automatically transfer data to Facebook the moment a user opens the app. This happens whether people have a Facebook account or not, or whether they are logged into Facebook or not.
‘The primary purpose of advertising IDs, such as the Google advertising ID (or Apple’s equivalent, the IDFA) is to allow advertisers to link data about user behavior from different apps and web browsing into a comprehensive profile.