Many of us use the WordPress sidebar to add important content blocks. In certain cases, it might make sense to add a popping/sliding sidebar to your site. These plugins let you do just that:
Popping Sidebars and Widgets: adds unlimited popping sidebars to your website. You can change positioning, overlay top, and other settings in the backend.
Ninja Kick: a sliding panel for WordPress with a responsive layout to display your content in a clean fashion. You can change background, padding, and effects in the back-end.
PopOut Content: lets you add pop out content to WordPress. Supports HTML content.
Popup Maker: a simple popup, modal, and content overlay plugin with customizable triggers, cookies, and conditions. It supports a wide variety of newsletter services.
Easy Slide-In: an attractive slide-in plugin with an optin module for top newsletter services. It gives you more flexibility promoting your content and works with WooCommerce.
Nest: adds fully responsive content panels to your website. It supports automatic and time-delayed activation. Each panel can be customized independently.
Collapse: a collapsible sliding panel for images, posts, videos, widgets, and everything in between. It has a drag & drop interface for sorting sections.
Which one of these plugins are you impressed with the most?