If you want to add plugin for Facebook, Twitter, LinkedIn, Google, Yahoo than can try
[http://wordpress.org/extend/plugins/loginradius-for-wordpress/](Social Login for Wordpress)
[http://extensions.joomla.org/extensions/social-web/authentication-cloud-based/19293](Social Login for Joomla)
[http://addons.oscommerce.com/info/8306](Social Login for osCommerce)
Above all plugins allow login from Facebook, Twitter, LinkedIn, Google, Yahoo and more in one platform using OpenID and OAuth.
Answers
If you want to add plugin for Facebook, Twitter, LinkedIn, Google, Yahoo than can try
[http://wordpress.org/extend/plugins/loginradius-for-wordpress/](Social Login for Wordpress)
[http://extensions.joomla.org/extensions/social-web/authentication-cloud-based/19293](Social Login for Joomla)
[http://addons.oscommerce.com/info/8306](Social Login for osCommerce)
Above all plugins allow login from Facebook, Twitter, LinkedIn, Google, Yahoo and more in one platform using OpenID and OAuth.