The system permits non-technically minded users to arrange content in pages and layouts, containing 'Assets' (applets) which permit website visitors to view and interact with various types of data from basic Articles to full-blown Content management system and custom applications.
WebGUI (pronounced web-GOO-E)
The system gives web administrators the ability to manage the appearance and features available in the user interface to fit each user's skill level. Its "users and groups" system allows control over content editing and viewing privileges, and the versioning and workflow systems allow for content approval hierarchies and tracking of content as it moves through the site. Everything in WebGUI is a template, which allows for customization, and keeps site content and style separate.
The system was originally built as an application framework by creator Plain Black Corporation to support their customer development work, but a majority of current independent users of it utilize it as a CMS with the modules with which it ships.
In late 2005 and early 2006, the system underwent a major metamorphosis, targeting a release of version 7.0 which occurred in mid-2006; the current versions are 7.5.32 (stable) & 7.6.2 (beta). 
In 1999, a development project called Web Done Right began in an effort to create a web application framework that married both ease of use and power. Over the next couple years, Web Done Right evolved, and after a number of revisions became WebGUI. WebGUI, and its parent company Plain Black Corporation, were launched to the public in 2001.
WebGUI contains many features that make it suitable for diverse organizations. WebGUI has a consistent user interface, which makes learning to manage content simple, and a number of “helper” applications, such as date and color pickers, aid in content creation. WebGUI also keeps style and content separate, which allows for quick and easy content management. WebGUI's versioning and workflow systems allow system administrators to set up content approval systems, and versioned site content can be “rolled back” if something is published to the site by mistake. WebGUI also assigns simple, easy to remember URLs to content applications, and images can be uploaded directly through the user interface. WebGUI has an e-commerce system, and internationalization features including local date and time display, and the ability to view the user interface in multiple languages.
WebGUI is built as an application framework, and has a pluggable architecture to aid in the extensibility of applications. Developers can create custom applications and functionality that match a company's business processes, and a pluggable macro architecture allows for even more extensibility and flexibility. WebGUI's modular design allows code to be easily accessed, changed, and replaced.
WebGUI is a mod_perl application but there is a project codenamed PlebGUI to port WebGUI to PSGI, the Perl Web Server Gateway Interface, which enables deployment using CGI, FastCGI, mod_perl, et al. 
With WebGUI, users can create:
In addition, there are many user contributed applications available.
WebGUI comes with a number of built in themes, and additional themes are available for free in the add-ons section of the WebGUI website. Everything in WebGUI is a template, and those templates are easily accessed through the admin user interface.
WebGUI has a translation server that allows anyone to contribute translated terms for any field label in the user interface. These translations can then be applied to a site and users can manage content in their native languages.
WebGUI is licensed under GNU General Public License, which means it is free to download and use.
To ease the installation of WebGUI's requirements, Plain Black distributes them inside of the WebGUI Runtime Environment (WRE). The WRE includes everything needed to run WebGUI, excepting some Perl modules that versions of WebGUI released after the WRE may require. The WRE is pre-compiled by Plain Black for their list of supported systems, and members of the community submit WRE binaries for other systems.
In addition to the requirements, the WRE includes tools to administrate WebGUI servers. The 0.8 version of the WRE introduced the WRE Console, which is a GUI tool (viewed with a web browser) to set up and manage WebGUI sites.