Facebook has added “subscribers” to its news feed page. Subscribers are basically folks who want to see all your public posts in their newstream, without actually having you agree to be their friend. You can turn off the ability for people to stalker, subscribe to you if you do not want this. Make sure your kids’ settings are changed as well; there are way too many creeps who are trolling FB pages for young victims. Most of the folks I know who use FB do so to be able to interact with people they actually know.”]
Source: http://www.shoaibyousuf.com/2011/10/change-your-facebook-privacy-settings.html