Simply put, an article directory is a website that serves as a host for article submission. This means when people sign up to be a member of an article directory—which is almost always free—they can write and submit articles to that directory. However, it doesn't end there. The article submitted by the member should contain a short biography at the end, complete with contact information (like an e-mail address) and an embedded link to his or her Web site(s).

Article directories essentially serve two major purposes. First, they are an excellent way to promote and drive traffic to your Web site, because article directories are such high-traffic areas. Writers and Web site owners actually use the service offered by article directories to make money off their own sites. How does this work?

As mentioned, when you become a member of an article directory, you write and post articles on almost any topic. In your bio at the end of your article, include a link to your Web site. This hyperlink counts toward your overall popularity in the search engines. People who read your article and are impressed with your content can then click on the link, which will take them to your Web site, where they can view more content and purchase your products or services.

The trick is to write about a topic that has to do with your Web site. For example, if you own a Web site that gives information about pet care and sells pet care products, write your articles for directory submission about pet care. If you're a writer trying to sell your services, you can write articles for directories about why quality, unique content is so important for webmasters.

This way, you'll get highly targeted (instead of random) traffic to your site. People who land on your article after a search and read it are obviously interested in the topic, so it only makes sense that if they click on the link in your bio that it will take them to more of the same content, and the ability to purchase products and services related to that content.

Another trick is to ensure your articles are well-written. Sloppy, haphazard “articles” full of fragments, incoherent thoughts, and spelling mistakes won't make you look professional or like an expert, and will greatly reduce the chance that readers will click on your embedded link to your Web site.

The best way to take advantage of article directories is to sign up with many article directories and submit articles to all of them. However, while this is generally free, it is quite a time-consuming endeavour, which is why many writers and webmasters choose to use special software that allows you to submit an article to many different article directories at once without having to do it manually—for a fee, of course. This makes using article directories a great form of viral marketing.

Secondly, article directories are used by webmasters as sources of free content to be used on their Web sites. When webmasters need appropriate and useful content to fill up their sites, and either don't have the time, the capacity, or the ability to write it themselves—or the money to pay for a Web content writer—then using content off article directories is a great alternative.

Keep in mind, however, that these articles are probably not exclusive—meaning that while they are unique to the author, they have likely been distributed to other article directories, the author may have used it on a blog or in a mailing list, and other webmasters may have picked it up—that's what you get for free. It's a quick, easy, convenient, and free way to get content on your Web site.