I require a list of popular online courses. This is not to include any
tertiary, secondary or primary courses (college/university/degree),
only courses that are about solving specific problems for people.

A great place to start is www.thelearningannex.com. This site has a
number of courses listed (which is perfect) but no indication of their
popularity. That is what I need to find out.

An example of the list would be (this is straight from learningannex.com):

1. Learn How to Fly - 3 Hour Video Program 
2. Crisis Investing -- How to Protect and Grow Your Wealth During
Perilous Times! - 2 1/2 Hour Audio Program
3. Overcome Procrastination Now - 2 1/2 Hour Audio Program 

Exact popularity ranking is not required. Just a good idea (20 or 30
courses) about what is selling in online courses.  Another good
example of what I want is Amazon's "Top Sellers", but in terms of
online courses that people are buying.

Please indicate sources of data and post comments if you are uncertain
what I require.

Thanks.