Why not YouTube, Twitch, Zoom, etc.? Hacktoberfest is all about community, and Discord has proven to be a great place to share progress and collaborate on open source work, all with a supportive environment. I also think that the way people engage takes many different forms, and I want a medium that supports that. For example, some people really like asynchronous chats. You can chat to your hearts content and skip out on video streams if you like.