The description metatag summarizes page content and may encourage clicks in search results. Some search engines use the description to help categorize pages, but more importantly, the page description may also appear in search results. A clear and persuasive description may not boost your search engine ranking, but it may encourage prospective customers to visit your site.
It’s important that your description metatag is readable and interesting, no longer than 256 characters, and also features one or two keywords that appear on the page, preferably placed near the beginning of the description.
If you’re struggling to think of a description, try using the first sentence or two from your page. iJoomla SEO automatically does this for you.