21 Mar 2016

Is CDN important for SEO?

CDN (Content Delivery Network) – a technology that allows you to deliver content to users in different regions: faster upload of images, videos, simple pages on your site. This article focuses on how people using the CDN could win in SEO and how not to lose the position and the traffic, including traffic from vertical searches. How to use the CDN properly to promote the site and not lose the traffic?

Ranking Factors

It is well known that search engines take into account only one ranking factor, which refers to the “speed” – this is server response time.

Certainly there is a number of factors that indirectly affect the rate of returning of content. The most powerful of them – is the average number of pages viewed on the site during the session. For the e-commerce segment , this figure is one of the qualities of the site measures, including search engines. The user visits your website, does not wait for it to load, and goes back to the issue. For Google, this is a clear sign that your site does not have useful information or isn’t user-friendly.

There are other factors: the average time spent on the site, the number of active actions on the site – BrowseRank takes this into account .

Download speed

Do not forget about the conversion. Does low site download have strong effect? Short session, when the person comes back, without waiting for the download – this is a very important signal for search engines that the site has no useful information or isn’t user-friendly.

Why are all these reasons related to e-commerce?

Suppose the real site loads 6-7 seconds. If we start from the conversion of 1.2%, we can increase the conversion rate to 0.2-0.4%. This will direct the company’s revenue, and this consumption should be commensurated with the cost of CDN, when you are thinking whether you need CDN or not.

Often the site can be downloaded a 110% higher than the average load time. If you have important clients from different regions, it makes sense to pay attention to the cause of this .

SEO for websites using CDN

We describe the pitfalls which come across people who use CDN.

CDN for SEO 1

Traffic decrease from Vertical Search: double pages, double content, work with subdomains.

Vertical search – a search for a specialized niche or category. Search pictures in Google – is the vertical search. Search for videos, search for cars – also vertical. Two basic vertical searches, which CDN helps to improve – are image search and video search.

Google looks at site speed

Usually there are 3-4 the most prominent points of the impact on site speed: the search results, the ranking of the contextual ads on site usability. Empirically, it was found that the direct impact on the ranking of requests has a response time to the server (not the full load time of the site). The difference in 0,1-0,2s. It may be significant, in equal conditions.

CDN for SEO 2

Google also takes into account the location of the site server.

Location of the server can affect if it is different from the location of the request. It is particularly important “in the regions.”


Generalizing and summing up all these facts, other studies and opinions, it can be said that the following site settings affect its efficiency (and the effectiveness of its promotion):

  • Server response time. Taking into account network latency, it should be less than 300ms. Even a slight increase in its negative impact on the number of pages and position (a negative effect of 10-30%).
  • The availability of the site (including the number of pages with server errors). Here, the negative effect wasn’t measured, but by analogy with the time of server response (decrease in the frequency of site visits crawler) possible loss of 5-15% of the positions, visitors.
  • Full load time of pages. Direct effect is difficult to estimate, it ranges from 5% to 20% while the loading time of your site more than 4 second.