A parked domain is one that's taken, but it's not associated with some other service - web or email hosting. Basically, this kind of domain address won't load any real content if you type it within an Internet browser, but nobody else can take it as you have already registered it and you are its owner. The advantage of acquiring a domain name and parking it afterwards is the fact that you are able to keep it and not stress that somebody else might register it in the meantime if, for instance, the website for it is not ready yet. You could set a short-term Under Construction website page for a parked domain while you're working on the website, or forward it to another web address - temporarily or permanently. The second option can be used when you have already registered domain.com, for example, and you acquire domain.net and domain.org, so that you can protect a brand name or a trademark. In this situation, the .net and .org domain names can be parked and forwarded to the .com since you don't need individual websites for them.