Meta Descriptions are placed in the <head> section of your web page in this format:

<meta name="description" content="--Brief description of the web page--">

Meta Descriptions should be a brief description of the content of that individual page. Meta Descriptions may show up in search engine listings along with the title of the page and the title of the website. Joomla 3+ CMS will add the <meta> descriptions into the HTML for your web pages from the information that you type into the text box in Article Manager, Category Manager or Menu Manager for that page. You can also add Meta Descriptions in other places that create a page, such as the Contact component.

For Articles and Categories, click on the Publishing tab and type in your description in the Meta Description text box. For Menu Items, click on the Meta Data tab to find this text box. You may also type a global meta description for your site in Global Configuration. If you do, this description will show up on every single page of your site if there is no replacement description. Some SEO experts will tell you that this is a bad thing, as Google does not like duplicate content. If you take this route, you are short changing yourself if you rely on search engines for traffic to your site. Meta Descriptions can be a good way to entice visitors to click on the link to your site. The better the description, the more likely the link will be clicked.

If there is a Meta Description for a Menu Item for a Single Article, it will override the Meta Description for the Article. If there is a Category Blog or Category List, the Meta Description will come from the information typed into the Category Manager for the blog or page listing, but the individual article page will have its own Meta Description from the Article.

So where is the best place to add a Meta Description on my Joomla site?

The best place to add the Meta Description is at the Article level. This description will always stay with the Article whether it is used for a Single Menu Item or in a Category Blog. If there is a Menu Item for that Article, you can add your Meta Description there that will overwrite the Article level description, but this Menu Item could be changed or deleted or pointed to a different Article, so having a description at the Article level is best. You should also add one at the Category level if you are going to have a Category Blog or Category List.

Another reason for having the Meta Description at the Article level is that you know where it is if you want to edit it. This keep organization at a better level.

Where do Meta Descriptions appear on the Internet?

The visitor that goes to a web page directly will not see the Meta Description when viewing the actual page. The Meta Description may or may not show up in the search result listings when someone types in a search term at Google. It is more likely to show up in the search results if it contains the search term words or key words. Meta Descriptions are now showing up in other places when people create links to the site, such as in Yahoo Mail and other services. Some 3rd Party Extensions will use your Meta Description to create OpenGraph tags for social sites like Facebook.

Here is an example of a search result from typing in the term "boxer dogs".

Screenshot of a search result

If you look at the source code for this page you will see the following <meta name="description" content="">

<meta name="description" content="All about the Boxer, info, pictures, breeders, rescues, care, temperament, health, puppy pictures and much more">

If you add a link in Facebook, and your site is set up with OpenGraph tags, your Meta Description will appear something like this below: