Is your private phone number on Facebook? What you should know...

If you have a friend on Facebook who has used the iPhone app version to access the site, then it's very possible that your private phone numbers - and those of lots of your and their friends - are on the site.

The reason: Facebook's "Contact Sync" feature, which synchronises your friends' Facebook profile pictures with the contacts in your phone.

Except that it doesn't do that on your phone. Oh no. Because that would be wrong, to pull the photos down from Facebook and put them on your phone. That would breach Facebook's terms of service.

Instead, what Facebook's app does it that it imports all the names and phone numbers you have on your (smart)phone, uploads them to Facebook's Phonebook. More...

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