A page's description meta tag gives Google and other search engines a summary of what the page is
about. Whereas a page's title may be a few words or a phrase, a page's description meta tag might
be a sentence or two or a short paragraph. Google Webmaster Tools provides a handy content
analysis section that'll tell you about any description meta tags that are either too short, long, or
duplicated too many times (the same information is also shown for <title> tags). Like the <title> tag,
the description meta tag is placed within the <head> tag of your HTML document.
Description meta tags are important because Google might use them as snippets for your pages.
Note that we say "might" because Google may choose to use a relevant section of your page's visible
text if it does a good job of matching up with a user's query. Alternatively, Google might use your site's
description in the Open Directory Project if your site is listed there (learn how to prevent search
engines from displaying ODP data). Adding description meta tags to each of your pages is always a
good practice in case Google cannot find a good selection of text to use in the snippet. The
Webmaster Central Blog has an informative post on improving snippets with better description meta
tags.
Snippets appear under a page's title and above a page's URL in a search result.
Words in the snippet are bolded when they appear in the user's query. This gives the user clues about
whether the content on the page matches with what he or she is looking for. Below is another
example, this time showing a snippet from a description meta tag on a deeper page (which ideally has
its own unique description meta tag) containing an article.
Good practices for description meta tags
• Accurately summarize the page's content - Write a description that would both inform and
interest users if they saw your description meta tag as a snippet in a search result.
Avoid:
• writing a description meta tag that has no relation to the content on the page
• using generic descriptions like "This is a webpage" or "Page about baseball
cards"
• filling the description with only keywords
• copy and pasting the entire content of the document into the description meta
tag
• Use unique descriptions for each page - Having a different description meta tag for each
page helps both users and Google, especially in searches where users may bring up
multiple pages on your domain (e.g. searches using the site: operator). If your site has
thousands or even millions of pages, hand-crafting description meta tags probably isn't
feasible. In this case, you could automatically generate description meta tags based on
each page's content.
Avoid:
• using a single description meta tag across all of your site's pages or a large
group of pages.
SEO - Make use of the "description" meta tag
