A meta tag is an element that provides information about the metadata of an HTML document. This information could be the keywords, author, page description or any other details about the specific page. Unlike other HTML tags, however, a meta tag is not visible or displayed in the concerned page.
Although most search engines have since stopped using meta tags for ranking, these tags are still considered useful for search engine optimization and also help in increasing the click-through rate of the website.
Meta tags are also known as description tags, meta description tags or metadata tags.
The syntax of meta tag is as follows:
<meta name = "type of meta tag" content = "content related to the meta tag" />
Meta tags are machine passable and can be used by Web services and search engines as well. They usually contain information about the page that cannot be represented by other HTML tags and are considered as a category of on-page optimization. Although initially all search engines used to index websites based on meta tags, overuse and cramming of meta tags resulted in most search engines using algorithms that are not dependent on meta tags for indexing.
There are different types of meta tags, the most common of which are meta keywords and meta descriptions. Although a meta tag has a minimal effect on the page rank now, it can still help in click-through rates as description meta tags do appear in search engine results.
When creating a meta tag, it should be accurate and relevant for the concerned page. This helps with the readability and also gives a genuine appeal to things. The meta tag should be short, clear and concise, and it is considered as best practice not to use the same meta tags across different pages or to duplicate meta tags.