Presumably Harvard doesn't have shareholders or owners that can take a profit from it's business. It's some form of nonprofit organization. It has a huge endowment, pays high salaries to lots of employees, but then so do other nonprofits.

All of Harvard's money goes back into the school. They don't have to show a profit and any money they make HAS to go back into the organization like any other non-profit.

Most colleges are non for profit institutions.

Many online college programs are not bound by this.

There's also the issue of focus (besides the other stuff mentioned): for profit schools are market driven, and therefore focus on programs that are in high demand, and generally very pragmatically minded (i.e. business courses, career and vocational courses, etc.)

The non-pragmatic courses tend to limited, and still pretty heavily focused on skill building rather than, say, literary analysis or deep history.

For example, one of my friends teaches (and is dean of general ed at) a local for-profit: she teaches general psychology, how to talk with/work with/manage others of different backgrounds (cultural competency), things like that - stuff that has job-based direct relevance.

Harvard et. all have some of the 'build skills' stuff - law, medicine, business, but a lot more of the 'study for the sake of the subject' or 'study for deeper background' or other stuff that's not as directly tied to employment.

I am sure there is more to it, but I think legally the difference is that a nonprofit school doesn't have to pay federal & state taxes, and donors contributions to them are tax-deductible.