To explain, expired domains come about as domains are only registered for a certain period. If the domain isn't renewed, then it will expire. Many expired domains have had a lot of time and effort spent on promoting them, so there are obvious benefits to be gained by re-registering an expired domain, such as ongoing visitor numbers.

Most passive revenue gained from an expired domain could come from advertising. It is worth noting that different adverts can pay different rates. For example, a financial services advert would normally pay more for a click-through than an advert for cooking recipes.

The more visitors your domain receives, the more clicks your adverts are likely to receive. So it is important to consider the number of links pointing to the domain, and the domains rankings in the top search engines. The more links and higher ranking, then the more visitors the domain is likely to receive.

There are websites out there that can provide this information on expiring, and expired, domains. You should seriously consider using their services in order to find your quality expiring domains, as they can vastly simplify your search.

So concentrate your search for expiring domains that will receive visitors and are based on a subject that will be attractive to advertisers. Once you have found an expired domain, and registered it, you will then need to consider your options.

A quick and simple option is to sign up to a domain parking service that will show adverts and split the advertising income with you. It may be quick and simple, but it is probably not the most effective use of your domain.

Instead consider building a website based on that domain. This may seem a daunting task, but with the help of a good teach-yourself-HTML book, free website templates, and a little practice, you may surprise yourself how quickly you can put together a website. Good content, and lots of pages, can be the key to a successful website.

To have a website you need to host it. There are many cheap hosting options from around $10 per year. There are even companies that offer free hosting - but make sure that the free hosting package allows you to use your own domain name.

With your own website you are then able to show your own adverts, or sign up to services such as Google AdSense which will show adverts for you.

You can also add links from this new website to any other websites you own, thus further promoting your other websites.

Links to third party websites can also be sold. If your new website is of a high enough standard, paid-for links can provide a significant income.

Building your own website is a harder task, and may involve an outlay for the hosting, but the income you can derive should outweigh the extra costs.