How big does my email list need to be before launching an Online Course?

Have you had an idea for an online course in the back of your mind for a while? You might’ve seen other people launch their online courses and now you’re thinking that you’d like to do that too and start earning passive income for years to come. However, this business model may be new to you, and you probably have a bunch of questions. For example, where do you start? How big does your audience have to be? Is it enough to have followers on social media? Do you need an email list?&n...