The +1 button announcement specifically says "share recommendations with the world" and the messaging around +1's has always been clear that they are public and

The +1 button announcement specifically says "share recommendations with the world" and the messaging around +1's has always been clear that they are public and associated with your identity. > Today we’re taking that a step further, enabling you to share recommendations with the world right in Google’s search results. It’s called +1—the digital shorthand for “this is pretty cool.” To recommend something, all you have to do is click +1 on a webpage or ad you find useful. These +1’s will then start appearing in Google’s search results. http://googleblog.blogspot.com/2011/03/1s-right-recommendations-right-when-you.html http://googleblog.blogspot.com/2011/03/1s-right-recommendati... > 1 is as simple on the rest of the web as it is on Google search. With a single click you can recommend that raincoat, news article or favorite sci-fi movie to friends, contacts and the rest of the world. http://googleblog.blogspot.com/2011/06/1-button-for-websites-recommend-content.html http://googleblog.blogspot.com/2011/06/1-button-for-websites...