via Docs Blog by Google Docs on 9/15/11
We have been thrilled with the response to the launch of the +1 button on websites all across the web, but we also heard that you’d like a simple way to add the +1 button to your own Google Sites. Adding the +1 button to your site will allow your visitors to recommend it to their friends and contacts, which helps more people discover it via their personalized search results.
Starting today, you can add the +1 button to any individual page by choosing +1 Button from the Insert menu, or you can add it to your site’s sidebar and have it appear on every page instantly by editing your Site Layout under Manage Site.
Try it out and let us know what you think in the forum.
Posted by: Michael Verrilli, Software Engineer