Google's photo-sharing service started to use Google Translate API to automatically translate comments in your interface's language. The translation is displayed below the original comment.
Of course, the translation is not perfect and Google didn't do a good job at properly disclosing that it's an automatic translation (there's a "Powered by Google Translate" tooltip when you hover over the translation). This is yet another integration of Google Translate in Google's services, after translating Google Reader subscriptions and YouTube's search results. What other services would you like to integrate machine translation?