As far as propelling your website to the top of the search engines, they don’t. While Meta tags have no significant impact on actual search engine rankings, they do provide value in how your website appears on a search engine results page (SERP).
Meta tags are basically text included in the source code of an HTML document that’s intended to describe the page to a search engine for the purpose of cataloging its content. There are two types of Meta tags – description and keyword
So do Meta tags matter?
Yes they do as the description found within the tag indicates what you want someone to see on a search engine results page. They help a searcher easily determine whether or not your page is relevant to their needs. Without it, many people will simply move on and think your site doesn’t offer them any value.
If you do not include a Meta tag in your source code, the search engine will glean your page and cherry-pick words it thinks best describes your page. This doesn’t work too well however and can result in terrible descriptions being displayed on a SERP.
You should be very careful in how you use a Meta tag though. Many SEOs have abused these tags in the past thinking it would garner them a competitive advantage. To avoid any potential problems, avoid repeating keywords and use only those words relevant to your site’s theme. Beware of any trademark infringements and check with legal counsel before using another company’s trademarked terms anywhere in your source code.
Typically, the character limit for both description and keyword Meta tags is 250, which includes spaces and commas. Anything past the 250 mark is generally ignored by the search engines.
Just be careful – improper use of a Meta tag could result in your site being penalized by the search engines.