We do a lot of A/B testing with Optimizely and Visual Website Optimizer. And SEO is our most important traffic driver. For most tests, we only change elements within the page, but recently we did a bigger test where we created a whole different page and had to redirect half of the traffic to the “B” variation. This variation was recognizable in the URL with an extra query string ?v=2. We discussed the implications for our SEO, because of course it’s not good to have several URL’s that have the same content. But, we thought Optimizely would handle this issue, as they also state in their knowledge base:
2. Specifying an alternative page to redirect a percentage of your traffic to. [...] is safe as well, although the paranoid tester may wish to take further precautionary measures. Here's a great blog post describing some of the steps you can take to make absolutely sure that your Google ranking remains unaffected: How to Combine Conversion Optimization with SEO -Part 2
But yeah, we should have been "paranoid"...
So, we launched this A/B test for our subject page: the page that lists courses for a certain subject, like assertiviteit (assertiveness) on our Dutch site. And of course, without us linking to the B variation, we suddenly saw it appearing in Google:
We should've just canonicalized them
OK, so what we will do with new tests is simply implement canonical URL’s (read Google’s explanation) in them to make sure search engines understand that the original page URL is still the one you want in the index. Of course you should also be careful to change too much content on the page at once, since that might hurt your rankings.
Let me know if you have any questions, share similar experiences if you had the and of course correct me if I’m wrong ;)
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