There's a myth that A/B testing hurts search engine rankings because it could be classified as duplicate content, which search engines don’t look kindly upon. This myth is most definitely false. In fact, GOOGLE’s Matt CUTT advises running A/B tests to improve the functionality of your site. Website Optimizer has a good breakdown of the myth too, and why it doesn’t hold up. If you're still CONCERNED, you can always add a "no index" tag to your variation page. Detailed instructions on ADDING a “no index” tag can be FOUND here.

There's a myth that A/B testing hurts search engine rankings because it could be classified as duplicate content, which search engines don’t look kindly upon. This myth is most definitely false. In fact, Google’s Matt Cutt advises running A/B tests to improve the functionality of your site. Website Optimizer has a good breakdown of the myth too, and why it doesn’t hold up. If you're still concerned, you can always add a "no index" tag to your variation page. Detailed instructions on adding a “no index” tag can be found here.