When using ‘meta data’ in reference to a web page it refers to the data that describes the contents of the page, or the ‘<meta>tags’. In an SEO sense metadata generally refers to the title tag, meta description and meta keywords, it can also include the meta robots tag and multiple other tags such as location and author. Search engines use parts of this meta data such as the title tag and meta description to display snippets of content on their results pages. The meta data cannot actually be seen on the web page itself but is instead contained within the HTML of the page and can be viewed on the page source.
SEO Considerations for Meta Data
Not all components of meta data, or meta tags are created equal. For example, Google claims not to take notice of meta descriptions or meta keywords due to the fact that webmasters have abused the system by keyword stuffing within these sections. There are a whole swathe of meta tags available to webmasters, but realistically there are only a handful that are priorities in the world of SEO.
To avoid falling foul of Google’s webmaster guidelines, make sure that your meta data is an accurate description of the content of said webpage.
A web pages’ meta data is contained within the <head> of the page’s HTML. For more information on the how to implement title tags, meta descriptions, meta keywords (although these are almost completely useless) and meta robots, please see their individual pages.
Meta Data is often autofilled using the title of the page and the initial content by most CMS’ and Google will scrape content off the webpage to create meta data to display on the results pages if it is not present. Furthermore, if the existing meta data is not deemed accurate enough by Google, the search engine may choose to display the information on the results pages differently to how it has been entered in the <head> of the page.