AB Testing

Has anyone here implemented the AB testing of a website front page? Does it influence on Google result?
(Currently key position have fallen from 1 to 9 (but still on a first page).)

I would like to find out if key phrases be changed (H1, H2, Anchors, etc.) on a test page?

Will this affect on search results? Please, I would appreciare if you shared your experience.

Concerning Product Page: which button is paramount?
Download or Buy?

Please share upon your own good/bad experience.

And what kind of texts have brought the highest conversion rate yet? What are the basic key words to accomplish purchase action: ““Order””, ““Buy””, ““See Price””, or any other, more reliable? The same with download action: ““Download””, ““Free trial””, ““Try free””, or any other, more reliable?

Would appreciate any wise advices

Odd that there’s two posts in such short order on this topic. Let’s keep the conversation in one thread, shall we?

Conversation continued here: http://www.sitepoint.com/forums/showthread.php?780699-A-B-Split-Testing