When you register a domain, your name, email, phone number, address is all entered into a public database & it can be viewed & used by anyone, basically it’s exposed to all public.
Privacy for Domains is very essential especially if you want to reduce identity theft, unwanted spam, Fraud etc. According to The Internet Corporation for Assigned Names and Numbers (ICAAN) rules you have to provide genuine contact information. ICAAN is the company that controls the use of domain names. Below is a domain privacy example:
A good domain privacy service helps protect the domain owner’s personal information from spammers and identity thieves and unwanted marketing efforts & will securely mask & substitute it with generic information provided by a proxy service operated by the web host company. Domain privacy services can be purchased from registrars through the domain that they register with. The details & information from the company registering becomes available through what is known as a WHOIS database. Unfortunately, these details is also available to marketers, promoters & even hackers who collect this information & use it to place you on mailing lists, spam your email & also attempt identify theft.
So nothing is 100% safe in the technology world but stay in control, you can decide what information you wish to make public through your actual website, just remember to provide safe contact information that your customers/users & yourself can feel comfortable using.