A parked domain address is one which is taken, yet it is not connected to another service - web or email hosting. Essentially, this kind of domain address won't load any real content if you type it in a web browser, but nobody can take it as you've already registered it and you are its owner. The main advantage of acquiring a domain name and parking it afterwards is the fact that you will be able to keep it and not stress that somebody else may register it meanwhile if, for example, the site for it is not ready yet. You can create a temporary Under Construction webpage for a parked domain name while you're working on the web site, or direct it to some other web address - temporarily or permanently. The latter option can be used if you have already registered domain.com, for instance, and you acquire domain.net and domain.org, so as to protect a brand name or a trademark. In cases like this, the .net and .org domains can be parked and forwarded to the .com since you don't need individual websites for them.