Facebook Like Lock WordPress Plugin
Facebook Like Lock for WordPress. Locks your content and user can unlock by clicking on like button.
Social Locker for WordPress
Social Locker is a WP plugin that locks your most valuable site content behind a set of social buttons until the visitor likes, shares, +1s or tweets your page. It helps to improve social performance of your website, get more likes/shares, build quality followers and attract more traffic from social networks.
Ninja Popups for WordPress
Ninja Popups combines a professionally designed popups to convert visitors on your site/blog into taking an action whether its subscribing into your newsletter, offering a discount/coupon for leaving customers, or locking content until they share you will increase your subscriber count and social signal of your site/blog.
Layered Popups for WordPress
With this plugin you can realize your imagination and make unique multi-layers WordPress popup windows. You can create multiple layers with whatever-you-want content and add custom transitions/animations for each layer.