Synchronous technologies – requires two or more people to be online at the same time, sharing a space, or communicating via text (chat) or voice. Examples include: webinars, chat, second life.

Asynchronous technologies – people are not online at the same time and interaction does not occur without a time delay, allowing people to participate on their schedules. Examples are email, discussion groups, and self-paced courses. (World Wide Learn 2008)

Video conferencing – live video and audio communication between three or more locations.

Email – short for electronic mail; primarily text messages sent between two computers.

Chat / IM – An online, real-time interactive communication method using text to send and receive instant messages.

Discussion forums / bulletin boards – a place where people can exchange messages of common interest.

Interactive TV – (generally known as iTV) describes a number of techniques that allow viewers to interact with television content as they view it.

Simulations – interactive multimedia presentations designed to model real scenarios and which allow the user to participate and experience without risk.

Multi-user games – a multi-player computer game that combines elements of role-playing games, hack and slash style computer games and social chat rooms. Typically running on an Internet server or bulletin board system, the game is usually text-driven, where players read descriptions of rooms, objects, events, other characters, and computer-controlled creatures or non-player characters in a virtual world. Players usually interact with each other and the surroundings by typing commands that resemble a natural language, usually English.

Second life – an example of a synchronous communication technology that is an Internet-based 3D virtual world.

Virtual worlds - A virtual world is a computer-based simulated environment intended for its users to inhabit and interact via avatars.