Meta description tags, while not important to search engine rankings, are extremely important in gaining user click-through from SERPs. These short paragraphs are a webmaster's opportunity to advertise content to searchers and to let them know exactly whether the given page contains the information they're looking for.

The meta description should employ the keywords intelligently, but also create a compelling description that a searcher will want to click. Direct relevance to the page and uniqueness between each page's meta description is key. The description should optimally be between 150-160 characters.