Viral Content Locker is a Joomla extension (module+plugin) that helps you spread the word about your website. With this extension, you can hide the content of your page so that visitors unlock it by sharing it on Facebook, Twitter, Google+ and LinkedIn.
Module: the module contains a text editor; you can insert a text there and then ask visitors to share it in order to read on.
Plugin: When the plugin is enabled, you can insert a simple code into your article thus hiding the full text or a part of it and showing Facebook (LIKE, SHARE or both), Twitter, Google+ and LinkedIn buttons. After visitors press one of theese buttons and shares the content on their social account, the whole article is displayed.