As a result of the application’s new “contact sync” feature, those using the service face having both their personal phone number and those of their contacts uploaded to the internet. When uploaded, the phone numbers will be automatically cross-checked with those of other members before allocating them to your online ‘phonebook.
Charles Arthur makes the following observation:
“The implications are huge, and extremely worrying. All it takes is for someone's Facebook account to be hacked (perhaps via their phone being stolen) and lots of personal details are revealed. Or, as [in one case], you get your phonebook record of "Steve Car" (a garage mechanic) somehow linked to someone called "Steve Carlton" - who you don’t know”
The only way, however, to ensure your telephone number is not shared in this way appears to remove this information from your Facebook profile.
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