This will allow visitors to share articles and pages they like on their Google+ profile, driving in new traffic for the site.
The plugin has many options, giving the webmaster complete control on how and where the button shows up.
In the Joomla backend, go to the "Extensions" -> "Install/Unistall" section.
Upload the package's ZIP archive file.
Here are some key features of "Google Plus One plugin for Joomla":
· Set a custom button size
· Show button before or after article content
· Show or hide button counter
· Exclude button from certain articles
· Exclude button from certain categories
· Add custom CSS code
· Joomla 1.5.x/1.6.x/1.7.x