Web conferencing may be used as an umbrella term for various types of online collaborative services including web seminars ("webinars"), webcasts, and peer-level web meetings. It may also be used in a more narrow sense to refer only to the peer-level web meeting context, in an attempt to disambiguate it from the other types of collaborative sessions. Terminology related to these technologies is inexact, and no generally agreed upon source or standards organization exists to provide an established usage reference.
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.
Presentation of visual materials most often is accomplished through one of two primary methodologies. The web conferencing software may show participants an image of the presenter's computer screen (or desktop). Again, depending upon the product, the software may show the entire visible desktop area or may allow selection of a physical area or application running on the presenter's computer. The second method relies on an upload and conversion process (most commonly consisting of Microsoft PowerPoint files, other Microsoft Office electronic documents, or Adobe PDF documents).
For example, if you’re hosting a webinar on how to use WordPress blogs, and participants are asking a lot about increasing traffic, you could position your email like this: “I’m getting a lot of questions about boosting traffic to your blogs, so I’m throwing in a bonus how-to guide which will be sold later for $97, but you’ll get it free if you act now.”
In 1996, PlaceWare was founded as a spinoff from Xerox PARC. In November of that year, PlaceWare Auditorium was described in a public talk at Stanford University as allowing "one or more people to give an interactive, online, multimedia presentation via the Web to hundreds or thousands of simultaneous attendees; the presentation can include slides (made in PowerPoint or any GIF-image editor), live annotation on the slide images, real-time polls of the audience, live audio from the presenter and those asking questions, private text and audio conversations in the auditorium's "rows", and other features." PlaceWare Auditorium was formally announced in March 1997 at a price of $150 per simultaneous user.
In general, web conferencing is made possible by Internet technologies, particularly on TCP/IP connections. Services may allow real-time point-to-point communications as well as multicast communications from one sender to many receivers. It offers data streams of text-based messages, voice and video chat to be shared simultaneously, across geographically dispersed locations. Applications for web conferencing include meetings, training events, lectures, or presentations from a web-connected computer to other web-connected computers.