That is something I’ve pondered about as well… and still don’t know. My physical address is all over the place, so I will most likely start with that.
I do know some people get very concerned over privacy issues, and I would think a Post Office Box would be one solution.
But for people that concerned over privacy, they might also check the Whois information for their website(s). Unless they paid extra to hide their personal information, the address they used to register their domain will be publicly available.