Modules
Modular programming is a software design technique that increases the extent to which software is composed of separate, interchangeable components called modules by breaking down program functions into modules, each of which accomplishes one function and contains everything necessary to accomplish this.
Conceptually, modules represent a separation of concerns, and improve maintainability by enforcing logical boundaries between components. Modules are typically incorporated into the program through interfaces.
A module interface expresses the elements that are provided and required by the module. The elements defined in the interface are detectable by other modules. The implementation contains the working code that corresponds to the elements declared in the interface. -- Wikipedia
Currently, there are over 8,061 extensions available to be incorporated into the Joomla! WCMS. You are once again forewarned of potential "geek speak".
A module, specifically in Joomla! are more lightweight and flexible extensions used for page organizing and rendering. These modules are mostly known as the “boxes” that are arranged around a component, for example: the login module. JSN ImageShow or the footer are also modules.
Modules are assigned per menu or page item. So, you can decide to show or hide the logon module depending on which menu item the user is viewing. Sometimes modules are linked to components such as the “latest news” module which links to the content and displays links to the newest content items. However, modules do not need to be linked to components, as a matter of fact they don't even need to be linked to anything and can be just static HTML or text. Examples: Login, Banners, Menus, Who's Online.
Modules can be complex and powerful or basic and simple. They can make up a substantial portion of a website, therefore the Joomla! WCMS has a specific Module Manager dedicated to handling them. From this manager one can easily move a module to a different area of the website or turn them on and off depending upon the needs of each page.
RE: is ready to assist you with their expertise with any of these technical units. You as our client, communicates your needs, and RE: will incorporate all of these powerful technical solutions to make your website look how you want it to. Please contact RE: with your website development requirements.