In an article titled, "When Professors Print Their Own Diplomas, Who Needs Universities," Jeffrey Young at the Chronicle of Higher Education explores some interesting developments in open education.
He notes that there have been several recent examples of faculty opening courses to students beyond those who are enrolled in the university. The most radical example might by David Wiley's agreement to allow students to not only take his course without enrolling, but agreeing to provide feedback through grading to these individuals and then offering them a self-made "certificate of completion." In general, it seems unlikely that this scenario will be widely adopted as it too time consuming and too personally costly for faculty to give away their time in teaching large numbers of students (paying or not paying) to create sustainable models that merely open-up classrooms online. However, it is possible create learning communities that provide access to a wider group of participants at various levels of engagement. Creating learning communities requires us to shift on thinking from having only two types of roles (teacher or student) to a model in which everyone in the learning community has expectations for being both a teacher and a student. In this model it is assumed that a great deal of how I will learn will be dependent on my efforts to creating opportunities for others to learn-- in short, "teaching" will a platform for learning or for being a student. In other posts, I have described some general ideas for the possible roles in this type of learning environment.
Rather than assume that professors are individually going to offer courses to increasing numbers of people it seems more likely that they are going to manage complex learning communities with students at many different levels of participation and engagement. This can result in more "open education" for people interested in the topic who want to obtain some insights into the current thinking and development on a topic, but it would also create an environment in which more advanced learning can take place that is not completely dependent on "one" instructor doing all the teaching.