Any site like FB , Google +, everyone needs to go thru each of the privacy settings first thing- and only allow close/family/friends to see your posts.

You can say no the address book /contacts part.

The generic settings allow for anyone to see everything.

Read the rules/info/help pages when you join a social media site like FB.

You can still go back and change your settings and unfriend anyone you don't want to be sharing info with.