Meta-elements, often-times wrongfully called meta tags, are pieces of information on an HTML page (web document), which are only interpreted by web-browsers and search-engines.
The attributes of a meta-element that are most relevant for the OnPage optimisation of a website are:
- description
- robots
- title
- (The title element is not really a meta-element attribute, but is also exclusively interpreted by web-browsers and search-engines, and is often placed in front of other meta-elements within the HTML source code)
Other meta-element attributes are:
- http-equiv
- keyword
- author
- copyright
- publisher
- property
- generator
- page-topic
- page-type
- language
- distribution
- audience
- allow-search
- domain
- doc-class
- reply-to
- revisit
- date
- abstract
- expires
- googlebot
The meta-element attribute “keywords” is no longer taken into consideration by Google and other search engines and is therefore not relevant for a good ranking.
Google doesn’t use the keywords meta tag in web search
– Matt Cutts
Available meta-element attributes, including their possible values
You will find a neat table of meta-element attributes, including their content (content=”value”), as part of Google’s Search Console Help.