A trademark for the term WEBinar (first three letters capitalized) was registered in 1998 by Eric R. Korb (Serial Number 75478683, USPTO) and was reassigned to InterCall. The trademark registration was cancelled in 2007. Learn.com filed a claim for the term "webinar" without regard to font or style in 2006 (Serial Number 78952304, USPTO). That trademark claim was abandoned in 2007 and no subsequent filing has been made.
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.
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.