Sync.ME asks for the basic user permissions in order to provide a Caller ID and phone search, properly sync your contacts and use all of the features in the app.
New permissions from Version 2.5.2 and higher:
"Phone Calls", and "Other Application UI" are phone permissions used for the Caller ID feature, so you can see who is calling you before you answer.
"Text Messages" is used to provide Text ID – allows you to see who texts you.
"Receive Reboot Event" is used for the Birthdays feature (Version 1.4.x) to recognize new birthday notifications when you turn on your device.
Those with CyanogenMod ROM and using "Privacy Guard" or apps that block permissions, note that the app will not function properly if the access to certain app permissions are removed. For example, if "Read Contacts" is turned off in Privacy Guard, then you will not be able to sync your contacts or see the updated contact list in the app.