Depending on the technology being used, participants may speak and listen to audio over standard telephone lines or via computer microphones and speakers. Some products allow for use of a webcam to display participants, while others may require their own proprietary encoding or externally provided encoding of a video feed (for example, from a professional video camera connected via an IEEE 1394 interface) that is displayed in the session.
Real-time text chat facilities such as IRC appeared in the late 1980s. Web-based chat and instant messaging software appeared in the mid-1990s. The PLATO computer learning system allowed students to collaborate on networked computers to accomplish learning tasks as early as the 1960s, but the early networking was not accomplished via the World Wide Web and PLATO's collaborative goals were not consistent with the presenter-audience dynamic typical of web conferencing systems. PLATO II, in 1961, featured two users at once.
In December 2003, Citrix Systems acquired Expertcity, giving it the GoToMyPC and GoToAssist products. The acquired company was renamed as the Citrix Online division of Citrix Systems. In July 2004, Citrix Online released GoToMeeting as its first generic web conferencing product. In June 2006, GoToWebinar was added, allowing additional registration and reporting functionality along with larger capacity in sessions.
Web conferencing software is invoked by all participants in a web meeting. Some technologies include software and functionality that differs for presenters and attendees. Software may run as a web browser application (often relying on Adobe Flash, Java, or WebRTC to provide the operational platform). Other web conferencing technologies require download and installation of software on each participant's computer, which is invoked as a local application. Many web conferencing vendors provide the central connectivity and provisioning of meeting "ports" or "seats" as a hosted web service, while others allow the web conference host to install and run the software on its own local servers. Another installation option from certain vendors allows for use of a proprietary computer appliance that is installed at the hosting company's physical location.
A webinar is a live, web-based video conference that uses the internet to connect the individual (or multiple individuals) hosting the webinar to an audience of viewers and listeners from all over the world. Hosts can show themselves speaking, switch to their computer screens for slideshows or demonstrations, and even invite guests from other locations to co-host the webinar with them.