Information that is public on your social network profiles can be visible and synced by Sync.ME, according to relative social network guidelines for third party apps. This does not include phone numbers - Sync.ME does not have access to phone numbers on Facebook and does not sync your phone number onto other devices.
According to Facebook's privacy guidelines, the following is always public information: Name, Profile Photo, Cover Photos, Friends List, Networks, Gender, & User ID. Here is more details about public information: http://on.fb.me/1MUTXnX
You can control which information others see about you. In order to make your information private, you can change this in your individual privacy settings on Facebook:
1) To view who can see your profile: Privacy Settings on Facebook.
2) To view what others can see in apps: Privacy Settings>Apps>Apps others use . Here you can choose which Facebook information is available to others who use apps with Facebook.
3) To completely turn off access to third party apps: Privacy Settings>Apps>Platform>Edit>Turn Off Platform
Note: Sync.ME users who have your phone number will be able to see info on your ME Card if you have created on.