Meta tags (or: meta elements) are read by the crawler of a search engine, processed and possibly used for the ranking of a website. Which meta tags are important, and how are they taken into account by Google?
The following meta element attributes are relevant to Google
The meta description is not used by Google to calculate the ranking in the search results. However, as a text excerpt in the search results (snippet), it is an important user factor. For the searcher, it is the first point of contact with your website and therefore significantly responsible for the click-through rate to your website. With the free SISTRIX SERP snippet generator, you can create suitable meta descriptions for your users.
<meta name="description" content="Here is the meta description.">
The title element is relevant for SEO, as it tells the search engine what content a page offers – it is an important factor of the approximately 200 Google ranking factors.
Even though it is not part of a meta element, it plays an important role: the title tag is the clickable title of a search result in the search results. Each page on your website should have a unique title that concisely describes the content for searchers and search engines alike.
<title>Here is the title of the document</title>
The value of the meta tag with the robots attribute tells the crawler of a search engine, whether
- a page may be included in the index (Index) or not (NoIndex)
- the links on this page may be followed (DoFollow) or not (NoFollow)
- the content of the page may not be used as a Featured Snippet (NoSnippet)
- the page Google has cached should not be displayed (NoArchive)
If a value is not explicitly specified, it is presumed to be “allowed”. A page without robots meta-information will therefore be treated as if the following was specified:
<meta name="robots" content="index, follow">
You can find more important information about the robots meta tag on Google.
The viewport meta tag is important for the correct responsive display of a website on mobile devices. If it is missing, most mobile browsers use a default viewport of 980px, i.e., desktop width.
This meta tag is not directly SEO-relevant. However, if you take into account that Google prefers mobile-friendly websites – especially for mobile search queries – and that Google can check relatively easily whether a page is mobile-friendly via this attribute, it becomes clear what significance this meta element has or can have.
<meta name="viewport" content="width=device-width, initial-scale=1.0">
The keywords meta element is irrelevant to Google
The rumour that Google uses the content of the so-called keywords meta element, often incorrectly called the keywords meta tag, for rankings, unfortunately cannot be laid to rest. Google has never used the keywords meta element for the ranking.
<meta name="keywords" content="I, want, to, rank, for, these, keywords">
We have made a preselection for this article and only explained a few important meta elements. A complete list of meta elements that are less important for SEOs than for developers can be found in the Mozilla Web Docs.
What Google says
If you have a good meta description tag, we will use that information or part of that information in our snippet (…). But if you're looking at the keyword meta tags, we really don't use that at all.
Source: Matt Cutts
A keyword meta tag is consistently ignored by Google! The meta description is an important first point of contact of the user with your website in the search results, but is not used as a direct ranking factor. The title is important for the user’s decision and is considered a ranking factor by Google.