The best way to ensure a web page ranks well in Google keyword searches is to make sure it is the only one on the web that includes the content on the page. In this way you avoid several web pages all having a somewhat equal possibility of being judged relevant for the particular keyword search. This increases the chance that this unique page will outrank other quite independent web pages that cover the same topic. That’s the theory and it seems to work out well in practice.
WordPress is a great software for producing blogs but out-of-the-box the WordPress content management system produces a series of pages that all contain the same content. Just see the concerns expressed in this WebmasterWorld thread about WordPress And Google: Avoiding Duplicate Content Issues where several coding suggestions were offered to avoid the problems. More recently, David Bradley has suggested that something called the canonical link element can be the solution to Avoiding Duplicate Content Penalties.
We should quickly add that this is not an inherent weakness of WordPress alone since many other CMSs will suffer from similar problems. It is a well known problem and you can find an excellent article on how to Avoid Duplicate Content on WordPress Websites, which gives the appropriate steps to take. The most important step of all is to have the right robots.txt file.
I wondered how well people were grappling with this duplicate content problem and decided to check out some of the Technorati’s Blogger Central / top 100 blogs. In particular I thought a check of their robots.txt files would give an indication on whether they had tried to solve the problem. Here is what I found for the robots.txt files for the most popular 8 blogs.
- The Huffington Post
- Boing Boing
- Ars Technica
- Stuff White People Like
As you may notice, the most popular blogs seem to have a singular disregard for this issue with minimal robots.txt files. As you come down the list, it would seem that even these top blogs realize the importance of limiting what the search engine robots crawl and index.
This could have resulted in many extra web pages that humans would likely not see but search engine spiders would certainly crawl. Changes were made in the site architecture to avoid this. To avoid other potential duplicate content problems, the current robots.txt file for this blog appears as follows:
Getting the robots.txt file correct is one of the easiest ways of increasing the visibility of your blog pages in search engine keyword searches. Leaving two essentially similar web pages means that the two divide up the ‘relevance’ that a single web page would have. That means approaching a 50% reduction in potential keyword ranking. Perhaps the top blogs can ignore such improvements but most of us should not. Check out what the spiders may crawl by doing an evaluation of your website with Xenu Link Sleuth. We should carefully consider our robots.txt files and make sure they are doing an effective job. Is yours?
Andy Beard added a comment that he has concerns about using the robots.txt file as a solution to the WordPress Duplicate Content problem. He explained these in a post some time ago called SEO Linking Gotchas Even The Pros Make. There is much food for thought there and we will follow up in a subsequent post.