The viewer sees what is on the presenter's screen real-time. At the end of the show, I was presented with an evaluation form to complete. Rick was on the speakerphone, amicably encouraging us to complete it. Since I was already at my keyboard, it was easy to do. The only downside for the presenter is that you have no faces to look at in the audience, and you can't gauge people's reactions.
Web seminars work.
Rick said this was the third live Webinar he had done. We got calls to our VP of Sales within an hour of doing a Webinar.