It's arguably simple, actually: 1. ICANN requires every registrar to display their domains' registration data in a public database called WHOIS, and it's part of every registrar's contract to ICANN. 2. Every registrar passes on that contract term to their end users, including a bunch of terms saying you agree to them and you waive any rights to any of that data except, say, credit card information. The moment you post information with someone, they're essentially free to do anything as they please with it unless: a) any applicable law exists covering it or so, or b) that someone agrees with you what to do with that information. It's nice if they do what Google does, but they're not required to do the same since ICANN says otherwise. Feel free to participate in ICANN's WHOIS debate that's been going on for the past seven years and counting, like I said. You'll be dealing with groups such as law enforcement who want data turned over at a whim, and IP groups who want WHOIS data displayed to pursue cybersquatters. Good luck.
I have an account in DomainTools and when I register a new domain they send me an email about that because I use the same email in whois and domaintools ... But they have the information even when I protect whois . I use godaddy doamin by proxy . So they are an " Insiders " .