A Webinar is a seminar which is conducted over the World Wide Web. It is a type of web conferencing. In contrast to a Webcast, which is transmission of information in one direction only, a webinar is designed to be interactive between the presenter and audience.

A webinar is 'live' in the sense that information is conveyed according to an agenda, with a starting and ending time. In most cases, the presenter may speak over a standard telephone line, pointing out information being presented on screen, and the audience can respond over their own telephones, preferably a speakerphone.

Webinar: http://en.wikipedia.org/wiki/Webinar