This plugin adds Google Plus One Button to every post on your WordPress Site. This plugin is simple and uses in built function to display Google Plus One Button below every post. The size property of the plugin is set to „standard“ and the annotation property is set to „inline“. Read about these properties here https://developers.google.com/+/plugins/+1button/
Dieses Plugin steht zum Download zur Verfügung, um in deiner selbst gehosteten WordPress-Installation verwendet zu werden.