Canonicalization

What is Canonicalization?

Canonicalization is the process used by website owners to specify the preferred version of a webpage for search engines and users. This is achieved through a "rel=canonical" meta tag or an HTTP header, which is added to the page's source code. The tag or header signals to search engines that the tagged page should be considered the original version and treated as the most relevant for search queries.

Canonicalization addresses issues of duplicate content, where the same content is accessible through multiple URLs. By specifying a canonical URL, it directs search engines like Google to present the preferred version in search results, reducing the risk of diluting link equity and confusing search results.

Example of Canonicalization

Consider a product available in multiple categories on an e-commerce site, accessible through different URLs:

• https://example.com/product/category1/item
• https://example.com/product/category2/item

To avoid duplicate content issues, the site owner can choose one URL (e.g., the first one) as the canonical URL and add a canonical tag to the other page(s). This tag will indicate to search engines that the first URL is the preferred one.

Does Google Crawl Canonical?

Yes, Google crawls canonical URLs. When a canonical tag is used, Google understands the indicated URL as the main one to index. However, Google may choose to ignore the canonical tag if it finds it inappropriate or inconsistent with the site's content structure.

Why is Canonicalization Important for SEO?

Canonicalization is crucial for SEO because it helps to:

1. Avoid Duplicate Content Issues: It ensures that search engines index only the preferred version of a webpage, preventing multiple versions from competing against each other in search results.
2. Consolidate Link Equity: By directing all links to a single URL, it consolidates link equity, which can improve the page's ranking potential.
3. Improve User Experience: It ensures users are directed to the most relevant or up-to-date version of a webpage.

Do Canonical Tags Affect SEO?

Yes, canonical tags significantly impact SEO. They guide search engines in understanding which page to index, thus influencing which version of a page appears in search results. Proper use of canonical tags can strengthen the SEO performance of the preferred page.

What is Non-Canonical in SEO?

In SEO, "non-canonical" refers to pages that are not marked as the preferred version. These might be duplicate or similar pages that exist alongside the canonical version. Non-canonical pages are often supplementary and should not compete with the canonical page for search engine ranking. The existence of non-canonical pages without proper canonicalization can lead to SEO issues like split link equity and diluted page authority.