Abstract Modules are special modules that are used to help build other modules. Developers can use these modules to build additional modules that share functionality. Currently the system has six abstract modules - activity stream, global, hideable, search, search2, and tabbed container.
The Content category of modules provides a variety of pre-configured and reusable search modules that can be placed on any page.
System Modules make up the backbone of the vBulletin Content System. These modules cover everything from displaying channels and topics to the user profile. While these modules have options that you can control, they should not be removed from pages or system functionality will cease working.
Last Modified: 12/20/2017