The term "webinar" is a portmanteau of web and seminar, meaning a presentation, lecture, or workshop that is transmitted over the web. The coined term has been attacked for improper construction, since "inar" is not a valid root. Webinar was included on the Lake Superior University 2008 List of Banished Words, but was included in the Merriam-Webster dictionary that same year.
Then you ask them follow up questions to make sure they understood your presentation, what they do not understand, what objections they may have, etc. etc. You will close more sales if you are able to get feedback from clients, and Webinars allow you to see their face, to hear their voice to know how they are feeling about you, your presentation, your company and your products and services.
Using Webinar software participants can share audio, documents and applications with webinar attendees. This is useful when the webinar host is conducting a lecture or information session. While the presenter is speaking they can share desktop applications and documents. Today, many webinar services offer live streaming options or the ability to record your webinar and publish to YouTube and other service later.