What Causes Webinar Attendees to Bail
People like presenters who grab their attention, even if they're not funny (although being entertaining doesn't hurt). But they do need to be sufficiently dynamic. Unskilled presenters who read from slides will bore attendees and see headcounts drop steadily throughout the session.
Webinar speakers also feel stress, although they are under less pressure than those at live events. Often, in technology sales, talented scientists and programmers don't turn out to be dynamic speakers. What you gain in authority at a webinar, you will lose in boredom. Consider sending such folks to speaker training or use a two-presenter approach. Adding a team member with great communication skills can offset a dry presenter.