Beta Testing is a stage in the design and development process of computer software and hardware that uses people outside a company, called “beta testers,” to be sure that products function properly for typical end-users outside the firm (Berkshire Encyclopedia of Human-Computer Interaction, V.2, p. 828).


CMC, Computer-mediated communication uses computer network technology to facilitate communication among geographically separated participants and includes computer conferencing, electronic mail, and on-line databases such as bulletin boards and newsgroups  (Berge & Collins, 1995; Harasim, Hiltz, Teles, & Turoff, 1995).


Critical mass is the maximum number of adopters from the target population needed for the success of an online community or any group .

GUI is a graphical user interface, pronounced "GOOEY". A user interface that presents information graphically, typically with draggable windows, buttons, and icons, as opposed to a textual user interface, where information is presented on a text-based screen and commands are all typed. It's often assumed that GUI applications are inherently more usable than text interfaces, but that may not be true when GUI applications are not well-designed. Graphics enable more flexibility in design and enable certain useful interaction styles (like direct manipulation), but text-based applications may still be extremely usable if they are designed through a user-centered process: gathering information from users, carefully designing the interaction tasks, conducting user testing, etc (Usability First).

HCI,  Human-computer interaction is a set of processes, dialogues, and actions through which a human user employs and interacts with a computer . A more recent definition states that human-computer interaction is a discipline concerned with the design, evaluation, and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them .


Interaction Design Interaction design is: “designing interactive products to support people in their everyday and working lives.”(Preece et al., 2002). It takes one step beyond Human-Computer Interaction (HCI), to include a broader scope of issues, topics, and paradigms. These steps reflect the changes in technology that we are experiencing, where there is a greater need for interaction designers and usability engineers to develop current and next-generation interactive technologies. For interaction designers to be successful they will need a mixed set of skills from different disciplines such as HCI, web-design, computer science, psychology, information systems, marketing, entertainment and business.


Interface is the interconnections between a device, program, or a person that facilitate interaction

Metaphor is the use of one idea or object to represent another; making an implicit comparison between concepts to provide insight into those concepts. Metaphor is used widely in graphical user interfaces to help set users' expectations and make the behavior of computers clearer. The "desktop metaphor" is used to suggest that a computer screen is like a physical desk, with papers and folders to shuffle around and various desk accessories, such as calculators, printers, and notepads. A general physical world metaphor is what allows a beveled border to suggest a button and allows close parallel lines to suggest that something is draggable. Metaphors are also useful techniques for designers to explore representations of concepts and the behavior of interface elements. Designers may also apply wild and unrelated metaphors as a useful brainstorming device. (Usability First:

Desktop Metaphor is the representation of familiar desktop items in a user interface to help make the capabilities of a computer clear. The prototypical example is the Macintosh desktop, which is used as a backdrop for all application windows and the surface on which files are manipulated. Files are organized into folders, and other objects including disks and printers, appear as icons on the background desktop. Traditionally, the Mac included "desk accessories", including a calculator, notepad, scrapbook, and clock that correspond to items a person might have on their desk. This organizing metaphor presumably makes new users more comfortable with the system and helps them to learn more quickly how to interact with it (Usability First:

Usability is a key concept in human-computer interaction (HCI) and it is concerned with making systems easy to learn and easy to use (Preece et al., 1994, p. 14). Shneiderman (1998) defines it according to how consistent, controllable and predictable a particular software application is for the intended users.


User Interface is the environment allowing a computer to interact with a computer (e.g. Windows). UI; the parts of a computer system that a person uses to communicate with the computer. This includes the way the computer conveys messages to the person (output devices), the way the person talks to the computer (input devices), and the steps the person must perform to do their task (Usability First).