For a long time, my perceptions of online learning were based on professional development trainings for things like CPR certifications or online Spanish vocabulary quizzes in college. Each course or lesson culminated in a quiz that tested my understanding of the content, and successful completion yielded a certificate certificate or an email to my teacher that I had finished the "tarea".
I usually half-assed these courses, letting the online video play while I was checking Facebook, or skipping the lesson entirely and then just guessing. If I got a question wrong, I would just hit the back button and try again. The problem was that these courses relied on summative assessment, but rather than pushing me to prove what I had learned, they ended up testing what I already knew.
The reason why my online masters has been so successful for me is that it has mainly relied on formative assessments that have helped me to build up skills and pieces before turning in the final project or product for each course. I still rely heavily on prior knowledge to get through my assignments (I used to think of this as "bullshitting", but since I have become a teacher, I prefer to think of it as "critical thinking"), but now I am pushed to think more complexly and add to what I know with each step.
I think this is the key to meaningful online education. Students cannot be allowed to simply sit through a lesson passively just to check a box so they can move on. It is true that this is important for face-to-face classes as well, but in online programs students rarely interface personally with their instructors, so the instructor never has a chance to observe the student to evaluate their level of engagement. Formative assessments allow for frequent check-ins, and ultimately more engagement for the student.
In designing an online course, I would probably do away with online quizzes altogether. Rather, I would challenge each student to come up with a deliverable that demonstrates what they understood. This could be a drawing, an essay, a joke, video, or whatever the student wanted to create that reflects their take-aways. This may take longer than your average quiz, but at least the student would have a portfolio of work they created by the end of the course.