use of World Wide Web to broadcast information. Unlike typical surfing, which relies on a pull method of transferring web pages, webcasting uses a "push" combination of technologies to send information to users' computers. This is also referred to as " broadcasting , channel surfing , or " netcasting ." Users get steady updates of streams of information in requested categories. Users can subscribe to a "channel," download software to a local computer, and then streams of automatic updates follow. The most popular webcasting service to date is PointCast , but several major companies, including Microsoft and Netscape, have announced their own webcasting products and services. For example Netscape announced it " Netscape Netcaster " as follows:
See also Listserv and Chat Lines .
One of the latest webcasting options is the Java-based Castanet that can be downloaded from http://www.marimba.com . When users subscribe to a channel with Castanet Tuner, it requests the download of the corresponding application from an Internet-based Castanet Transmitter server. Castanet Tuner then saves the Java application onto your hard disk. When launched, channels can either operate locally without a live Internet connection or (where appropriate for the channel's type of content) communicate across the Internet. In the past, web casting was free of virus risks. With the advent of Windows Scripting Host utilities, this is no longer the case. Precautionary advice is given under ActiveX . See also Intercast .
The next generation of metadata webcasting will probably be in Resource Description Format (RDF) . There were various metadata processes before RDF was on the drawing boards. Microsoft's Channel Definition Format (CDF) used in "Web Push Channels" and Netscape's Meta Content Framework (MCF) preceeded RDF. These technologies describe information resources in a manner somewhat similar to RDF and can be used to filter web sites and web documents such as filtering pornography and violence. They can be used to channel inflows of desired or undesired web information. CDF, for example, carries information not read on computer screens that perform metadata tasks. See Resource Description Format (RDF) and Search engine .