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Regarding EU cookie law: understanding its implications

A large number of Visual Website Optimizer’s customers are based out of Europe and given the EU Cookie law (EU Directive 2009/136/EC, PDF opens in new window) we’ve decided to write a clear guide to how Visual Website Optimizer uses cookies and how should you interpret / understand this direction (note: we recommend you to consult your lawyers, this post is merely our understanding of the situation). In this post, we will elaborate on:

  1. What are cookies anyway?
  2. What does EU cookie law mean for you?
  3. The difference between first party and third party cookies
  4. The cookies used by Visual Website Optimizer
  5. How to opt out of Visual Website Optimizer tracking?
  6. Other useful links

What are cookies anyway?

On this topic, gives a very succinct answer:

“Cookies are small files which are stored on a user’s computer. They are designed to hold a modest amount of data specific to a particular client and website, and can be accessed either by the web server or the client computer. This allows the server to deliver a page tailored to a particular user, or the page itself can contain some script which is aware of the data in the cookie and so is able to carry information from one visit to the website (or related sites) to the next.”

What does EU cookie law mean for you?

Actually, we believe there is still uncertainty in its interpretation and implementation. However, if you are a Visual Website Optimizer customer based out of Europe, please read and understand what your country directive is (since EU law also differs from country to country). That said, the common consensus seems to be this: a website must inform its visitors that: a) cookies are being set on their computers/devices; b) explain what cookies are; c) communicate why cookies are being set and what sort of cookies are being set; d) give them an option or inform them how to opt-out of cookies/tracking.

To see how different websites are implementing this policy, we recommend you to read this excellent article by eConsultancy: 20 examples of EU cookie law compliance.

The difference between first party and third party cookies

Cookies are usually associated with one particular domain (the domain they are set on) and only that domain can access the data contained in the cookie. A first party cookie is where the domain you visit and the cookie owner are the same. For example, you visit and the cookie information also says

A third party cookie is when you visit a certain domain, but the cookie dropped by that domain on your computer identifies itself as belonging to someone else. For example, you visit but the cookie dropped has the information

Visual Website Optimizer by default only uses first party cookies. However, if you have cross domain tracking enabled in the test, we use third party cookies to track conversions across multiple different domains. Please see details on Cross Domain Tracking feature to get more information. Note that only if your tests run across multiple domains simultaneously should you be bothered about third party cookies.

The cookies used by Visual Website Optimizer

VWO uses cookies to keep track of the variation a user has seen, the goals a user has completed and even whether a visitor has become a part of the test or not. To know which all cookies are being set by VWO and their usage, please see this article in knowledgebase.

How to opt out of Visual Website Optimizer tracking?

For visitors: in case you want to opt out of tracking by Visual Website Optimizer, simply go to our Opt-Out page input the website URL on which you don’t want to be tracked. This will generate a link, clicking on which will exclude you from any kind of tracking by Visual Website Optimizer.

For website owners: in case you want to provide an option to your visitors so that they can opt out of tracking by Visual Website Optimizer, please enter your website address in our Opt-Out page and copy the generated link. You can then share this link with your visitors. Once they visit the link, they will be excluded from any kind of tracking by Visual Website Optimizer.

Useful links

Please see the following links for a better understanding of what’s happening with EU cookie law and how it might affect your business and your visitors:

Hope you found this post helpful. Do let us know if you have any questions or feedback.

I do marketing at VWO.

Comments (2)

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  1. The new EU directive about Internet cookies has raised major concerns between online marketers and writers, especially those depending on Adsense and other form of advertising or affiliate sales income. In my personal view, I think that there will be a drop initially and after an adjustment period, when Internet users will have got used to the idea, advertising income will return to normal.

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