Duplicate Content has long been an issue with webmasters and is cause for concern because duplicating content dilutes your ranking in search results. Perhaps the most common cause of having duplicate content is in allowing both www. and non www versions of your site to exist. However, another place where I see duplicate content occur is when a customer has multiple domain names pointing to the same content. When you use multiple domain names, and there are good reasons to do this, you should pick a preferred URL and ensure that any secondary domains are 301 redirected to that URL.
In this video, Google’s Greg Grothaus does a great job explaining duplicate content problems and solutions ranging from 301 redirects to canonical tags.
I have previously blogged about how 301 redirects can prevent common problems from diluting the search engine ranking for your site. However, there are however a number of situations that create duplicate content concerns that are more difficult address. Webmasters now have additional tools to deal with duplicate content through Google’s Webmaster Tools panel. Through this addition to webmaster tools, Google Lets You Tell Them Which URL Parameters To Ignore. This will a great help, especially for many large dynamic sites.
This article has been updated to address additional questions received on this topic.
I am frequently asked about whether to use the www or not in the URL. While many of us are predisposed to typing the www, most of the time including the www is immaterial as typing either www.mywebsite.com or mywebsite.com will usually take you to the same place. So which should you use and when?
The answer is either, but not both and here are specific cases to consider:
Declaring one or the other is important as search engines will see www.mywebsite.com and mywebsite.com as different websites and index each independently (Google lets you declare a preference in Webmaster Tools). This has the undesirable effect of dividing the rank for your content between the two sites. While this may seem odd, www is technically a sub-domain and legitimate sub-domains such as jobs.yourdomain.com, support.mydomain.com, and so on are common.
So why does it matter, wouldn’t having two versions of your site in the engine double you chances of being found?
Let’s say you have a product page called product.html and three clients place links on their websites to the page as www.mywebsite.com/product.html, while two others link to to the page as mywebsite.com/product.html. All other things being equal, if a competitor had five links to a single page www.competitorwebsite.com/product.html, the competitor’s page would outrank yours.
To avoid having a duplicate version of your website in the search engines, decide whether to use the www or not and create 301 re-directs (typing the undesired one will redirect to the desired version) to enforce that decision. Then add both to Google’s webmasters tools and declare the preference in site settings.
I mention on my SEO page that having a descriptive URL is a good thing. In the example I say that www.huntsville-bike-parts.com is better than having www.bobsbikes.com. Why?? — You know that incoming links (sites linking to yours) are very important, perhaps equally important is the phrase that links the URL. When you have a descriptive URL, this link and phrase association are one and the same.
For example, here I have linked the phrase Search Engine Marketing to www.marketing-ontheweb.com.
