Meta tags accumulate. A page picks one up from a tutorial, another from a plugin, a third from a checklist written in 2011, and ends up with thirty lines in its head section of which perhaps six have any effect. Knowing which is which saves both bytes and confusion.
The ones that genuinely matter
The title tag is the most important piece of on-page metadata there is. It is a direct ranking factor, it forms the clickable headline in search results, and it labels the browser tab. Aim for roughly 50 to 60 characters, front-load the meaningful words, and be aware that Google rewrites titles it considers unhelpful about a third of the time.
The meta description does not affect ranking, which leads some people to skip it — a mistake, because it heavily influences click-through rate. A well-written description on a fourth-place result can attract more traffic than a dull one in second place. Around 150 to 160 characters works for desktop, with mobile truncating nearer 120.
The canonical link tells search engines which URL is authoritative when the same content is reachable at several addresses. On any site with query parameters, pagination, or both www and non-www variants, it prevents your own pages competing with each other.
The viewport meta tag is not an SEO tag at all but breaks mobile rendering entirely if omitted, which has obvious consequences. And the robots meta tag controls indexing at the page level — the correct way to keep a page out of search results, unlike robots.txt, which merely prevents crawling.
- title — direct ranking factor and the clickable result headline.
- meta description — no ranking effect, large click-through effect.
- link rel=canonical — resolves duplicate URLs to one authoritative address.
- meta viewport — required for correct mobile rendering.
- meta robots — page-level indexing control, including noindex.
Social tags: worth the four lines
Open Graph tags control how your page appears when shared on Facebook, LinkedIn, WhatsApp, Slack and most messaging apps. Without them, platforms guess — usually badly, picking an arbitrary image and the first text they find.
The four that matter are og:title, og:description, og:image and og:url. The image should be 1200 by 630 pixels; anything else gets cropped unpredictably, and text placed near the edges disappears. Keep it under 5 MB and make sure it is legible at thumbnail size, because that is how most people will see it.
Twitter Card tags serve the same purpose on X, which falls back to Open Graph when they are absent. Adding twitter:card set to summary_large_image is usually the only one worth including, since it upgrades the layout from a small thumbnail to a full-width preview.
The ones you can safely delete
Meta keywords has been completely ignored by Google since 2009 and was announced as such publicly. It does nothing except advertise your keyword targeting to competitors, who can read it in your page source. Delete it.
Meta author, meta revisit-after, meta rating, meta distribution and meta language have no effect on any major search engine. Revisit-after in particular is a persistent myth — no crawler has ever honoured it. Language should be declared with the lang attribute on the html element instead.
Meta refresh redirects deserve a specific warning: they are bad for accessibility, disorienting for users, and a poor substitute for a proper HTTP 301 redirect. Use a server-side redirect.
- meta keywords — ignored since 2009, actively counterproductive.
- meta revisit-after — never honoured by any crawler.
- meta author, rating, distribution — no search engine effect.
- meta refresh — use an HTTP 301 redirect instead.
Structured data is where the effort should go
If you have finished with meta tags and want to invest further, structured data delivers considerably more. JSON-LD schema markup lets you describe what a page actually is — an article, a product, a recipe, a piece of software, a set of frequently asked questions — in a form search engines parse reliably.
The payoff is rich results: star ratings, FAQ accordions, breadcrumb trails and other enhancements that occupy more space in the results page and attract more attention. These are not guaranteed, but they are impossible without the markup.
Start with Organization and WebSite schema at the site level, BreadcrumbList on every page with a hierarchy, and then whichever content type fits each page. Validate with Google's Rich Results Test before publishing — malformed markup is worse than none.
Key takeaways
- Five tags do almost all the work: title, description, canonical, viewport, robots.
- Open Graph tags are worth adding; without them, platforms guess badly.
- Meta keywords and revisit-after do nothing and should be deleted.
- Structured data offers more upside than any remaining meta tag.