Each domain registered must have contact details publicly available for that domain so that the owner may be reached if necessary. The contact details are stored in a WHOIS database and WHOIS information for all domains can be found online using a number of WHOIS sites.
Information such as your name, postal address, e-mail address, phone number, etc. are usually listed publicly in the WHOIS database for anyone from the public to access. Private registration acts as a middle man so that instead of you personal information listed as the contact details for the domain, 1&1's company name, address, phone number, etc. are listed instead. Please see below for the contact data use for Private Registration.
1&1 Internet Limited
154 Southgate Street
will be listed for all contacts. A recorded message will explain that the domain owner can be contacted via a form. The recording will not accept any messages.
The e-mail address email@example.com
will be listed for all contacts. This e-mail address will reply to all messages with an automated reply containing link to a contact form the individual can use to contact you. Once the individual submits the form, the message will be forwarded to the e-mail address you have on file for you 1&1 account without revealing your e-mail address to the individual.
Other Important Points
For additional information, you may want to reference: