To help users test the latest +1 button, Google just introduced a new option for webmasters. "Enroll in the Google+ Platform Preview, available globally, to test updates before they launch to all users on your site. When you're logged into the account you've enrolled with and you visit a page with the +1 button, you'll see the latest preview release, explains Joshua Ganderson, Software Engineer.
"If you join now, you'll be able to test the first set of updates we've released to Platform Preview: hover and confirmation bubbles."
If you hover your mouse over a +1 button, you'll see a bubble letting you know what will happen when you click:
After you click, you'll receive confirmation that the +1 has been applied. This will give your site's users an extra reminder of the account they're using to +1, as well as the fact that their +1 is public.
Google's +1 button was launched in March this year, to share recommendations with the world right in Google's search results. To recommend something, all you've 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.
The beauty of +1's is their relevance--you get the right recommendations, at the right time and in the right format.
For more info about +1, read diTii.com's blog post here, and watch the video below:
[source: Google Webmaster Central]