WordPress, like any other blog software, allows blogger to concentrate more on blogging instead of the intricacies of creating and uploading a new page and make available the links to the new page via related pages.
The problem is, one blog post or content appears in multiple pages on the blog. This poses a duplicate content problem for search engines. Is it a real problem?
Duplicate content in WordPress especially falls under one of these conditions:
- Posting only once a day. The exact same content should be available at least in the homepage (if you display only the latest post), the permalink, and date archive page (/year/month/date/ for example).
- Displaying only one post per page. Content should be accessible at least through the permalink, date archive page, category pages (/category/name/page/x/), blog home pages (/page/x/).
- Assigning more than one categories to a post. This risks of having even more duplicate content across multiple categories.
- Using calendar or monthly archive. Yet another place where duplicate content can appear is in the daily archive (calendar) pages and monthly archives.
Sometimes the differences in the duplicate content pages are only in the title tag of the posts and perhaps some metadata information.
This problem often leads to pages being marked as supplemental pages in Google result pages. This is not good, because they are not available for main index but only for result pages where not enough results exist for the searched terms.
If your blog is doing well on search engines, perhaps you don’t want to do anything with it. But as your blog grows, it might be of an issue for you though.
Webmaster World forum recently has a discussion thread about this.
Some of the proposed solutions include:
1. Adding meta content in the header
Ask search engines not to index some pages. You can add the extra information between the <head> and </head> section of the page. In WP, you could do it by modifying the header.php file of the theme.
If you want allow search engines to index only homepage, permalink for blog posts and static pages, add the code below:
<?php if(is_home() ¦¦ is_single() ¦¦ is_page()){
echo '<meta name="robots" content="index,follow">';
} else {
echo '<meta name="robots" content="noindex,follow">';
}?>
Note: Please make changes and use the code very carefully. I have a blog which one of its category pages ranks very well in Google and brings me quite some traffic. You might lost traffic if you fail to plan properly.
2. Use excerpts for indexes
Avoid displaying full post in every pages but in the permalink of the post. Personally, I like full posts but still this is a solution to reduce duplicate content issue.
Assigning the same categories for a set of posts will end up with duplicate content in some places though. But the chances are much less if you also implement the third method below.
3. Display multiple entries on indexes
Having multiple blog posts in index pages like categories, date archives, and others reduce duplicate content in more than one pages.
Using both excerpts and multiple entries make the duplicate content appear even less frequently.
4. Use category specific template
WordPress allows you to assign specific template page with a category. Just add category-.php template file into the theme directory. You can find the category number in the “Manage Categories” section in your dashboard.
By creating unique content page for each category, you can create unique pages across multiple categories.
5. Using robots.txt
If you utilize wildcards in robots.txt, it applies to only Googlebot. The standard defines that no wildcard in robots.txt only applies to the “User-agent” string.
The following code in robots.txt
Disallow: /categories/
will disallow indexing of all content starting with /categories/, including folders and files beneath it.
Final note: Again, some bloggers never have problem using WordPress regarding duplicate content in search engines. But if you suspect the culprit of your problem in search indexes is in duplicate occurrences of the same post, you may want to try one of this method.
