You may have heard of meta tags before. These are a series of HTML tags that are visible to search engines but not to those who visit your website. There are many kinds of meta tags, but the two encountered most often for search engines are the meta keywords and meta description tags.
The meta keywords tag typically contains a list of keywords pertaining to information found on the website. In general, this list should contain 10–15 words and phrases, separated by commas, that describe a particular page of your website. The list should be ranked by importance, with the most important word or phrase listed first.
The meta description tag is a brief description of the content of your website. It may be used by Google in the search results page. The meta description should be short, no more than 150–200 characters in length. It should provide a good overview of the page's content. Make sure it also contains good keywords, which will catch the interest of someone who is considering visiting your page.
There are two places to configure meta keywords and meta descriptions in Joomla. In the Global Configuration, they can be configured for the entire website. You can also override the global setting on an article-by-article basis, by modifying the meta tags in the article editing windows.
In the back end of Joomla, go to Site Global Configuration, and look under the Site tab. A screen similar to the one ...