Recently Google added the Google+1 button. This seems to be Google’s most direct attempt to compete with the Facebook “Like” button, which allows your blog to be easily rated. In addition the +1 activity also will show up in Google’s search results. The button also provides a current count of how many times your story has been liked on Google Search Engine.
A plugin for WordPress was also released to make this button a breeze to install. The WordPress plugin – Google +1 Button works well with New Facebook Share Plugin and TweetMeMe button. All three plugins works great together. You can see 2 of these plugins currently installed on Rankbydesign.
For non-Wordpress sites the +1 button can be installed on Google Webmaster Central.