As per ICANN regulations, Whois databases store contact info for the owners of all registered domains. Name, address, phone number and email address are all listed. Whois also contains domain availability status, registration/expiration dates and related info.
Most domain registrars (NityGity, for example) offer Whois Lookup options, such as the one you find above. Legally, anyone who performs a Whois search can view the stored information. If that makes you stop and wonder about the security of your own private information, NityGity offers WhoisGuard privacy protection option to its customers.
You might not want your personal contact info to be accessible to anyone who searches the Whois database. We understand. That’s why NityGity provides WhoisGuard privacy protection with every domain registration or transfer. WhoisGuard replaces your contact info with NityGity contact info in the Whois database, so your personal information does not go on public record. WhoisGuard is very affordable (only $5 per year).