For antiquated reasons, ICANN rules require that Whois data, the data that describes the owner of a domain (like wintipsweb.us) and the contact information for that owner, be valid. This database has become a feeding ground for spam harvesting and outright stalking.
A common way to work around the problem is to provide false contact information, especially a false e-mail address, but this is dangerous. There are many examples of users losing their domains because their own registrars could not contact them through their contact information. Some domain registrars have developed an added-cost workaround to the problem by offering a private domain registration system.
Instead of seeing your information, a Whois user sees information about the registration service. If someone tries to contact you, the contact goes through the anonymity service. You set rules for whether you want contacts to be able to send information to you and for which ones can do so. The main downside to this system is the cost.