+1 helps people discover and share relevant content—a website, a Google search result, or an ad—from the people they already know and trust. The +1 button appears on Google search, on websites, and on ads. For example, you might see a +1 button for a Google search result, Google ad, or next to an article you're reading on your favorite news site. +1 helps drive visitors to your pages or ads, and because people can easily share and discuss your content, it increases engagement with your site. (Once you’ve added the +1 button to your pages, you can use the +1 Metrics tools in Webmaster Tools to see the impact of the button on your search traffic.)
Adding the +1 button to pages on your own site helps users and the people in their circles discover the great content on your site. Just by adding the button to your site, you get these features:
- Firstly, users can recommend your content, knowing that their friends and contacts will see your recommendation when it's most relevant—in the context of Google search results. They can also share your content right away, without having to leave your site.
- Secondly, when a user hovers over a +1 button, we'll suggest other content of interest on your site. The more +1's and Google+ activity a website's pages get, the more personalized these recommendations can be. Users who are signed in to Google+ will see recommendations personalized based on their interests. For example, we might show pages popular among all Google+ users, or pages popular among readers of that specific page, or even pages popular among readers in the user's circles. All you need to do is add the +1 button to your site—we'll display some recommendations even if the user isn't signed in to Google+.
When a user +1's a piece of content, that +1 appears in several places:
- On the +1 tab of their Google Profile. (While +1's are always public, people can choose to make the +1 tab visible or invisible on their profile.)
- Personal annotations in search. When a user hovers over the +1 button on a search result, we'll display the faces of friends and social connections who also +1'd that content.
- Personal annotations on your site. You can display a personalized annotation directly on your web page. More information.