Start? It wasn't that long ago that the phone company published a book with near everyone's phone number in it.
A cell phone number does not equal your kitchen phone in terms of access to information. The whole this is moot. The issue now is that this is my personal phone number, me, personally, and is being used as a piece of validating information in a variety of compromises databases.
I used it at a summer job in the late 80’s. You could order reverse lookup books for anywhere you wanted, and of course could get that data electronically too. You could also call information for anywhere you could think of by dialing the area code plus 555-1212.
With the twitter leak millions of phone numbers/names are available for free instantly, and the technology to do some harm with them is readily available.