What personal information can be obtained given only a phone number?
What information is your phone number publicly (or privately, but with easy access) linked to?
Here is the way I am looking at it:
Your phone provider knows your name and physical address. Additionally, they may know your email address, your SSN, etc.
Disregarding the possibility for a breach of the phone provider's data, are individuals or organizations able to obtain this information? Do phone providers sell or distribute this information in any way?