So what exactly is a meta description? Here is the official definition according to Moz.com:
“Meta descriptions are HTML attributes that provide concise explanations of the contents of web pages. Meta descriptions are commonly used on search engine result pages (SERPs) to display preview snippets for a given page. 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.”
On the web your meta is your “elevator pitch” to entice readers to want to know more about your content, and can be just as important as a creative headline. So even though creating meta descriptions may seem pesky and irrelevant, written properly they can influence whether someone chooses to click through on your informational links or not. Your chosen meta descriptions can be any length, but search engines generally truncate snippets longer than 160 characters. Though meta does not influence Google’s ranking algorithms for normal web search, they are helpful in pulling up preview snippets on search result pages for potential readers to see.