As a professional WordPress designer or developer, you need to be thinking ahead as you build sites for your clients. And, one of those things you need to keep an eye out for is duplicate content and its impact on your client’s SEO. When two pages have the same content, search engines won’t rank them both. Instead, Google, Bing, and the like will typically rank the page that published the content first, then ignore or penalize any other pages with the same content.
While the website’s copywriter can sometimes fix this, there are situations where duplicate content is either needed or unavoidable. If that’s the case, it’s up to you to specify the preferred page by using a canonical tag.
An Introduction to Canonical Tags
Pioneered by search engines in 2009, canonical tags are essentially hidden links created with the canonical element as a solution to websites with pages that include duplicate content. For example:
- You may have multiple variants of a landing page or blog post
- You have different or alternate versions of your site that are indexable
- Your site uses dynamic URLs
- You publish content that is syndicated
- You have blogs or forum posts with multiple pages of comments
Setting a canonical URL provides directions to the search engine as to which version of a page should be displayed in their rankings. This is especially useful if you are working on/with a website with a large number of pages. With canonical tags, you ensure that the search engine bots and algorithms crawl the correct pages.
Canonical tags consist of the canonical element and a URL. The URL is called the canonical URL, and it’s the page that search engines will rank in cases of duplicate content.
Fortunately, setting canonical tags in WordPress is pretty simple, and the process of implementing them depends entirely upon whether you’re using Yoast or another SEO plugin. Alternately, you can choose to add self-referential canonical without plugins by adding a snippet of PHP code to the header template file.
But – as with most things – there are several mistakes you should avoid making when using canonical tags.
1) Using Multiple Canonical Tags on a Single Page
No page should contain more than a single canonical tag. Canonical tags are designed to specify the preferred page in a series of pages featuring duplicate content. There can only be a single preferred page in any given series, so you shouldn’t use multiple canonical tags on a single page.
You can reuse the same canonical tag on multiple pages. For instance, if six pages have the same content, you can add the same canonical tag to five pages. The remaining page will be the preferred page, which should be mentioned in all five canonical tags.
2) Combining With Redirects
Avoid combining canonical tags with redirects. Both canonical tags and redirects allow you to specify the preferred page in a series of pages featuring duplicate content. Redirects, such as 301 or 302 status code redirects, use redirection technology to transfer search engines and visitors to the preferred page.
Combining canonical tags with redirects is pointless. You can use either of these solutions to optimize your website’s duplicate content. Combining redirects with canonical tags with redirects, in fact, only increases the risk of error. If you accidentally enter the wrong page address for a redirect, search engines may rank that page rather than the preferred page mentioned in the canonical tag.
3) Using the HTTP Format
Don’t use the hypertext transfer protocol (HTTP) format for canonical tags. Assuming your website is available over hypertext transfer protocol secure (HTTPS), you should use the HTTPS format. In other words, the preferred page mentioned in a canonical tag should be prefixed with HTTPS.
Websites that are available over HTTPS are typically available over HTTP as well. Search engines, though, prefer HTTPS for rankings. If a canonical tag mentions a page that’s available over HTTPS, you should use that format instead of the HTTP format.
4) Placing in the Body
When using canonical tags, you need to place them in the right section. Placing a canonical tag in the body section of a page won’t work. Search engines will only honor canonical tags if they are placed in the head section.
If you place a canonical tag in the body section of a page, search engines will disregard it. They’ll still crawl the entire page, but they won’t honor the canonical tag. Search engines disregard canonical tags placed in the body section and other non-head sections. Therefore, the page containing the canonical tag may rank, whereas the preferred page may not rank. If you’re going to use canonical tags, be sure to place them in the head section.
5) Prohibiting Crawling
Prohibiting search engines from crawling pages that contain canonical tags is another mistake to avoid. If a page contains a canonical tag, you probably don’t want it to rank. After all, the purpose of using a canonical tag is to specify the preferred page to search engine. But search engines still need to crawl the page containing the canonical tag to honor it.
If you prohibit search engines from crawling a page that contains a canonical tag, they won’t be able to see it, nor will they be able to honor it. Search engines may even rank the page with the canonical tag. Using the disallow robots directive doesn’t prevent them from ranking a page; it only prevents search engines from crawling it.
6) Specifying Preferred Pages With Original Content
The preferred pages that you specify with canonical tags shouldn’t have original content. If a page has original content, the page’s address shouldn’t be mentioned in any canonical tags. You should only specify preferred pages that have duplicate content.
Canonical tags are used for duplicate content SEO. When multiple pages have the same content, you can use canonical tags to denote a single, preferred page to search engines. Specifying preferred pages with original content is a mistake. Search engines may rank those select pages, but they won’t rank the pages that contain the canonical tags.
7) Omitting Canonical URLs From Sitemap
Assuming your website has a sitemap, you should include all of its canonical URLs in this file. Canonical URLs, of course, are the preferred pages mentioned in canonical tags. They are the pages that you want search engines to rank. Omitting them from your website’s sitemap could result in search engines overlooking them.
Search engines will choose canonical URLs regardless of whether they are mentioned in canonical tags. According to Google, its algorithm determines canonical URLs based on several factors, including HTTPS usage, sitemap inclusion, and canonical tags. By including canonical URLs in the sitemap, you can help Google choose the right preferred pages to rank.
You can include or exclude the unpreferred pages – the pages containing the canonical tags – in the sitemap. As long as the unpreferred pages have a canonical tag, search engines shouldn’t rank them. With that said, the preferred pages should absolutely be included in the sitemap. Otherwise, Google may choose different canonical URLs.
Chances are, your website probably has duplicate content. See for yourself: log in to Google Search Console and navigate to Search Appearance, then HTML Improvements. This will produce a list of all duplicate content identified by Google.
So, you should implement canonical tags instead of crossing your fingers and hoping that search engines rank your preferred pages. Just remember to avoid making the canonicalization mistakes identified above.
Did You Know Your Choice of WordPress Host Can Impact SEO?
In the last few years, Google has placed higher importance on speed, uptime, and security when it comes to ranking websites. While there are many things you can do as a professional website designer or developer to optimize WordPress sites, choosing the right WordPress hosting partner is one of the easiest and most important.
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Want to learn how Pressable can help your website enjoy better SEO? Schedule a demo today and learn more. And, in the meantime, check out these other articles to learn more about SEO optimizing your WordPress websites.