A parked Internet domain is one that's taken, however it's not connected to some other service - web or email hosting. In other words, this type of domain won't open any real content in case you type it within a browser, but nobody else can take it as you have already registered it and you are its owner. The main advantage of getting a domain name and parking it afterwards is the fact that you can keep it and not worry that somebody else might register it meanwhile if, for example, the website for it is not ready yet. You can create a temporary Under Construction webpage for a parked domain while you're working on your website, or forward it to another web address - temporarily or permanently. The latter 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 domains can be parked and forwarded to the .com because you do not need different websites for them.