Using The Meta Description
From Joomla! Documentation
The meta description tag allows you to provide a summary of the content of the page in one paragraph. The tag can be used by search engines to display a description of the page when displaying it in search engine result pages (SERPs).
Do I Need to Include a Meta Description? I Thought Search Engines Didn't Use Them Anymore?
With the advent of contextual "semantic" markup that allows a website to provide a context for the information, sometimes search engines will find more relevant information within the page itself or from other sources that link to that page (such as DMOZ) and use that in preference to your meta description. This does not mean that the meta description is not used, it simply means that if more relevant information is found to describe that page in search listings, a search engine may use that information rather than your supplied description. In fact, Google recommends that every page on your site has its own unique meta description and provides suggestions about writing your snippets.
Recommendations for Creating Meta Descriptions
When preparing meta descriptions for your pages, keep the total character count to fewer than 160. There is a limit to the number of characters displayed in search results pages. If you exceed this your text will be truncated. The meta description (if used) is one of the key factors that a person searching uses to decide whether your link is relevant to their search, so make sure that it makes sense to read, contains your keywords, and explains what is on the page. It is possible to dramatically improve your click-through rate in search engines by making sure your meta descriptions are well optimised and relevant to the content on the page.
Google recommends the following to ensure that you gain the most from your search engine indexing:
- Ensure every page has unique, relevant meta descriptions.
- Ensure you apply metadata for listing pages (e.g. blog & list layouts) in addition to individual articles. This is commonly overlooked on Joomla! websites.
- Include factual information if relevant (e.g. blog articles may include the author, products might include the price or manufacturer).
- Consider using automatically generated metadata - but make sure it's relevant, readable and accurate.
- Make your descriptions descriptive!
Joomla! Has a Global Setting for Meta Description Doesn't It?
Joomla! does indeed have a global field for meta description, which you can find under Administrator → System → Global Configuration → Site tab → Meta Data Settings → Site Meta Description. This will be used on any page within your site that does not have its own meta description specified, so it can be a "get out clause" if you don't want to create a meta description for each page, however search engines do not like duplicate title or meta description tags. Using this approach you will inevitably have many pages with the same meta description.
Consider carefully if you wish to complete these fields. The meta description in Global Configuration can often be left blank.