They have been the focus of a field of marketing research known as search engine optimization (SEO), where different methods are used to provide a user's website with a higher ranking on search engines. Prior to the rise of content-analysis by search engines in the mid-1990s (most notably Google), search engines were reliant on metadata to correctly classify a Web page and webmasters quickly learned the commercial significance of having the right meta element. The search engine community is now divided as to the value of meta tags.