what are meta tags used for
Meta element. Meta elements are tags used in HTML and XHTML documents to provide structured metadata about a Web page. They are part of a web page's head section. Multiple Meta elements with different attributes can be used on the same page.
Since keyword Meta tags have been used in conjunction with shady website optimization tactics, most search engines have decided to disregard them. Bing seems to be even more determined, and goes the extra mile to penalize website owners who count on this type of black hat SEO strategy.