A discussion of Google Web Optimizer

There are a lot of valuable resources out there which discuss the benefits of increasing conversions as well as how to get started, however I have noticed there is a lack of tools for webmasters to use to optimise their sites. Much of this is down to the fact that MV testing is a fairly new field. It has only been in the last 4 years that tools have become available and browsers technically capable of handling these. In addition only huge companies such as Google have the resources to develop marketing tools and then release them for free.

Website Optimizer is of course one of Google’s ever expanding set of webmaster tools aimed at increasing your traffic and ultimately conversion rates. As noted in previous posts conversion optimisation is the final step in the initial sale (although far from the final step in the business-customer relationship) and as such a key part of the sale. The benefits of Website Optimizer are numerous:

  • First and foremost it is free. This opens up multivariate testing to users who are not able to stump up the cash for commercial products. Of course you are thrown in at the deep end, since there is no payment there is no consultation or support with the provider.
  • The tool has a pretty good setup wizard, allowing you to create multivariate experiments fairly simply (though nowhere near a simple process as it could be)
  • It has a good dashboard showing the results, plenty of inline explanation and guidance including FAQ and guides. These are a great resource for working to tool.

website optimizer dashboard

Tom Leung has presented a good introduction and demo which is well worth watching at

Unfortunately there are problems with Website Optimizer as well. These are the ones that I have come up against:

  • Technicality of setup. The amount of code you have to paste into your pages is bewildering. Website Optimizer requires you to specify which elements of the page you wish to vary by adding in little snippets of code around the area you are interested in. Now admittedly this isn’t hard for someone with experience of HTML, however it could certainly be simplified.

website optimizer setup

  • Lack of HTML compliance. The code required to specified elements looks like this:

<script>utmx_section(”Insert your section name here”)</script>


This is invalid in both HTML and XHTML, Lennart has a nice piece on the reasons behind writing valid HTML at The interesting thing is that this could be easily fixed by simply using a different delimiter to signify the end of a section for example:


(The variable utmx_end would be defined in an earlier script file to avoid javascript errors)

  • No dynamic pages. As you have to put in alternatives as HTML it becomes very difficult to include dynamic data. Because you can include Javascript it is not impossible however. Mike Duncan demonstrates how to do this at In a world where 99.9% of e-commerce site are dynamic this is a major oversight. Admittedly it is a not simple to implement however I personally can think of several ways of doing it.
  • Durability of cookie. Many people block cookies or clear them at regular intervals (e.g. when the browser is closed). This means return visitors are likely to see a different version of your page and if they convert only the last variation they see will be tracked as causing that conversion. There are many other ways of persisting client side data that could be used. Paul Duncan has written a Javascript library, PersistJS (, that uses some of these ways
      I am interested in finding out what other benefits and problems users have encountered. What features would you request? Please feel free to leave your comments below.