Are you careful about your online security? Have you been sensible over the years about what information about yourself you choose to share with Facebook?
Good. Well done.
Unfortunately, it isn't enough.
Because, you don't just need to be careful about what information you *yourself* have uploaded to Facebook. You also need to worry about what *other* people might have been sharing about you.
The truth is that, even if you have never had a Facebook account, the website might know your email address and phone number because of what your friends, acquaintances and colleagues might have told the website - perhaps unwittingly.
Facebook encourages its users quite strongly to allow it to rifle through your email accounts, hunting for details of people in your address book, in the hope that it will help them build up a detailed picture of who you are connected with outside Facebook, their email addresses and contact phone numbers.
Facebook says it does this in order that it can provide better "friend suggestions" for you. There's a good explanation of how Facebook uses your address book to do this and the privacy breach which has exposed millions of its users, in this article by Naked Security contributor Paul Ducklin.
The upshot of it all is that if you imported your contacts into Facebook, you could have made life that little bit riskier for your friends and acquaintances. And they might not feel too happy if they knew that you had shared information with Facebook which they *themselves* would never have chosen to share with the site.
How to remove all your imported contacts from Facebook
So, here's how you resolve the issue.
Remove all of your imported contacts by visiting this page on Facebook.
Note that if you do decide to remove your imported contacts, Facebook's suggestions as to who you should connect with may reduce in quality. But that's a small price to pay for helping respect your friends' privacy.
Do your bit to raise awareness of this issue by sharing this advice with your Facebook friends.
Also, be sure to Like "Graham Cluley Security News" on Facebook to keep up to date on the latest privacy and security risks threatening users.
And remember to always be careful about what information you share on Facebook - not only about yourself, but about your friends, family, acquaintances and colleagues as well.
How to unsync Facebook from your iPhone/iPad contacts:
Go to the Settings app on your iPhone or iPad, scroll down and choose 'Facebook'.
You should now see a section entitled "Allow these apps to use your account". Tap the slider to "Off" for Contacts. Then click on "Update".
Hat-tip: F-Secure's Sean Sullivan