An online college has a lot of startup costs, unless you're just making a diploma mill. You need to get enough profs to teach a degree's worth of classes, especially if you're getting accreditation. (also, as an aside, the accreditations that matter require you to have a few years of successful classes). You also need a system for handling communication with teachers and students, grading, actually giving the lectures, and education software is not cheap. So as you hopefully can see, its not really bootstrap-able or easily scalable. You need money, and you need to get it right the first time, because you'll lose that money if you don't get enough students. Also, you need to be able to operate at a loss for several years, because it will take a long time to get accreditation. College is a lot about signaling - thats why it matters where you actually go. A few credits from a brand new online college is not great on a resume, so there will not be as much demand.

So, how about instead you try to take the tutorial concept and and apply it to practical skills? 2 classes of biology from an online college isn't really useful to someone. 2 classes of SEO or knitting or 'How to contract with the federal government' is really useful to people. This would also make it easy to recuit instructors. You could find retired people who just got out of an industry and want to make a little more money, or working professionals who want the feeling of giving back.

Here's kind of a short vision for a site i think has a shot at being successful. Have bios of the instructors, spelling out how they can actually give you good instruction in the course they're offering. Let people apply - advertise a class size capped at a certain number of people, and be upfront about costs. You split the cost with the instructor, so they only get paid if they bring in business. Don't use an essay, its a big barrier to conversion. Have people write 100-200 words on why they want to take the class, what experience they have in the area, and their future goals. Let the instructor choose who to take if more people apply than the class size. Bootstrap your way to more and more courses - and make the courses practical skills. There are a million websites that will teach me biology or history or math - most of them free and a lot better than what you'll be able to do. There aren't a lot of places where i can get someone to teach me how to transition from being an employee to consulting or get started in commercial real estate or start bidding on government contracts.