What is that line of text within your source of your web page that says  <meta name=“description” ? Very simply put, it is a brief summary of the content on the particular page.  Each page has it’s own meta-description, but most sites that have a meta-description already installed keep the same description for most to all pages of the site.  It makes life easy to just copy and paste something that works for a whole theme for your site, however having a unique meta-description for each page of your site will allow each page to compete evenly with each other.  When you have the same description for each page you are actually outranking yourself and pushing other pages of your site down the rankings of search results.

Take time and effort with this process because this is also what shows up in the search results, giving the searcher a little information about you page and will be in sync with the page <title> itself.

Meta-Description results from Source Code on Google.com

If you don’t choose to put in anything in your meta-description, Google will extract a brief summary of the page and post that on search results until you put something in the description itself.  Then you have to wait until the search engines come back to the site and re-index the pages to update the meta’s if applicable.

Using keywords where ever possible is always a plus, but do not use this area to stuff more of your keywords, you are only going to harm your rankings and/or get banned from the results.