When it comes to blogging, the number of authors that can be on a blog is pretty limitless. As long as the blog is functioning and has a clear and concise mission, there are no rules in place that limit the number of authors that can be on a blog.
In most cases, the more authors that are on a blog, the better because it creates a stronger and more diverse voice. This allows readers to connect with different perspectives and to learn from a variety of sources.
Ultimately, the number of authors that can be on a blog is up to the blog owner and their readers. As long as there is a clear purpose and direction for the blog, as well as an open dialogue among its authors, then there is no limit to how many authors can be on a blog.