Extensions (also called add-ons or plugins) are components which enhance the functionality of WYSIWYG Web Builder. Extensions can be accessed through the Toolbox or via the Insert menu just like the standard objects. In the future we plan to release a wide range of extensions to make WYSIWYG Web Builder even more powerful than it already is. Some extensions are simply components with few parameters while other are almost complete applications by themselves!
http://www.wysiwygwebbuilder.com/extensions.html