“Public speaking is the leading fear for all humans everywhere”.
Source: Some guy on some stage.
I can’t validate the accuracy of this adage but it is likely that people, in general, fear lack of acceptance, inadequacy and failure on both a proverbial and physically big stage.
There are a number of ways to improve your public speaking from taking a course, hiring a coach (I suggest Ben Decker of Decker Communications), joining a club such as Toastmasters or studying a lot of great TED talks are all ways to gain confidence with such a task.
There is no reason to fear public speaking when you do the proper preparation and have strong subject matter expertise. With that said, like with any other talent, it needs to be trained and honed to gain true mastery… or at least escape the self-sentenced prison of terror you occupy at the mere suggestion of addressing a crowd.
The best part of massive group communications is to be able to connect with the masses and pass along great ideas via positive vibes. If you help just one person see the world slightly differently, your time was well spent!