Parked Domain
A Parked Domain is a domain that reflects the same content as your main domain while retaining the Parked Domain address in the visitor's URL bar.
This is best explained through an example. If your main domain name was example.com, you could setup a parked domain name for example.org. Every time someone typed example.org in a web browser, the content of example.com would display, retaining the URL example.org in your address bar. Further, parked domains have full email functionality, so you would be able to have email addresses, aliases, and forwarders for [email protected].
It's important to understand that Parked Domains do not inherently redirect to the domain they are parked on. It is possible, however, to redirect visitors to your main domain after they visit your site through a Parked Domain. Without a redirect configured, the Parked Domain will remain in your visitors' URL bar.
Two common uses for Parked Domains are to catch frequent misspellings of domains and to control all related assets for your brand.
Frequent Misspellings
If your domain is example.com, your visitors might, for instance, frequently misspell it as exapmle.com. If you wanted to catch these misspellings and route the traffic to your site, you can register exapmle.com with your registrar and park it on top of your main domain example.com. When handling misspellings, it's usually desirable to redirect users back to the main domain so they do not bookmark the misspelled domain.
Google does this. If you try visiting googel.com, you'll be redirected to the google.com home page.
Controlling your Brand
If you own example.com, you may want to prevent a rival example company from registering a similar domain and gain traffic from your brand. You can register example.org and park it on top of your main domain example.com. If you prefer that your visitors use your main domain to visit your site, you can catch the traffic and perform a redirect.
Along these lines, you may also want to park domains that are aliases of your brand. The Internet Movie Database is most commonly visited via:
However, they also own the domain:
http://internetmoviedatabase.com
Visiting the latter link will redirect you to the former.