A parked domain address is one that's taken, but it is not associated with any other service - web or email hosting. In other words, such a domain address won't open any actual content when you type it in a web browser, but no one else can take it as you've already registered it and you are its owner. The best thing about getting a domain and parking it afterwards is the fact that you are able to keep it and not worry that someone else might register it meanwhile if, for example, the site for it is not ready yet. You could set a short-term Under Construction webpage for a parked domain name while you're working on your site, or direct it to some other web address - temporarily or permanently. The second option can be used if you have already registered domain.com, for instance, and you obtain domain.net and domain.org, so as to protect a brand name or a trademark. In such a case, the .net and .org domain addresses can be parked and forwarded to the .com since you don't need individual websites for them.