You should still hide the information, if you so desire. But don't lose your shiz over this.
If you've signed onto Facebook today, you've probably seen this warning blasted everywhere:
ALL THE PHONE NUMBERS of your contacts are now on facebook! go tothe top right of the screen, click on ACCOUNT, click on EDIT FRIENDS, left side of screen and click CONTACTS. you will see all phone numbers from your cell phone (FB friends or not) are published that you have stored inyour mobile phone. TO REMOVE, go to the right column, click on “thispage.” please repost this on your status, so your friends can remove their numbers and thus prevent abuse if they do not want them published.
While we encourage you to follow these instructions if you want your privacy, we want you to know that this information has been out there for awhile and if you wanted your privacy, you probably already have it since you know how to use settings.
And anyway, the main reason for this feature is to link you up to people you might know but aren't friends with on Facebook. So really, its not a huge deal.
But please, do what makes you feel safe and secure.