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/
Questo plugin è disponibile per il download da usare sulla tua installazione WordPress ospitata personalmente.