Even with using a cell phone number, it's ridiculously easy to find information about people. I used to work for a bank and we had access to a website where you could do free searches on people. You then paid if you wanted the report with all the details. I searched my name, found my SSN plus I was slightly linked with my parents', found every address my parents and I ever lived at as well as some property my dad put in my name and sold 10 years prior. If I had pulled the report, it would've shown full information about my car/license, any tickets, any properties I own, any businesses I'm apart of. Scary stuff.
When I had just met my now husband whilst working there, I did a search on him (and he has a common name). That was it. The search found his SSN plus every address he lived at. And that was just the free search.
So you can do a PO box to avoid giving out your address, but it is very easy to find. Oh, and you could search people by any phone number, including your cell.