I spotted an interesting comment from Google's JohnMu at the Google Webmaster Help forums. John said that in some cases, using Google Translate to auto-translate content for your web site might be seen as "creating auto-generated content, which would be against our Webmaster Guidelines."
I believe this is the first time I have seen a Googler say this, at least in response to using Google Translate to translate your content. Maybe John is saying this is a no-no when it comes to taking other people's content, running Google Translate on it and publishing it on your own site. I am not sure if he makes a distinction here. Let me quote JohnMu fully:
I just want to add a word of warning here -- using automated translation tools to directly create content for your site could be seen as creating auto-generated content, which would be against our Webmaster Guidelines. Instead of just taking the output of a program like Google Translate, I'd strongly recommend at least having it corrected before putting it online. While Googlebot may initially fall for some Spanish keywords in your text, your users are not going to appreciate content that has been automatically translated and published without a review. I love Google Translate, but if you publish the results and get them indexed without having them reviewed, you're not showing a lot of respect to your users...
You see, I am not sure if John is making a distinction between using it to translate content you wrote or not. It seems the point John is making here is that when you translate content using Google Translate, you must have someone manually look it over or else Google can penalize your site somehow because it is against Google's Webmaster Guidelines.
John is saying that using Google Translate, without manual intervention of some sorts (maybe even on your own unique content), is the same as creating auto-generated content, which is not in accordance with Google's Webmaster Guidelines.
Am I reading that right?
Forum discussion at Google Webmaster Help.