What is WHOIS Privacy?
People who do not want their personal information like contact details, e-mail information to be displayed to the public will prefer for a private registration. This is to avoid spammers from accessing the personal information to annoy the domain owner with unwanted emails, calls etc. Whoever does a whois search by using lookup tools like WhoisXY.com will be able to view only a third party(mostly the host provider) details hence even if they have to contact the domain owner they will be filtered by the third party. This is just to protect the domain owner