OEDb: online courses and the invisible web

From the Online Education Database (OEDb), 10 Advantages to Taking Online Classes:

1. Degree Programs and Classes Offered
2. Lower Costs
   
3. No Sitting in a Classroom
4. Choosing Study Times
   
5. Flexibility in Completing Assignments
6. Options when Returning to the Workplace
7. Balance a Job and Class
   
8. Avoid Adverse Weather Conditions
9. Specialized Degree Programs
   
10. Transfer Credits

And OEDb founder Jimmy Atkinson has just published an article warning that the visible web is but the tip of the iceberg, explaining:

Google, the largest search database on the planet, currently has around eight billion web pages indexed. That's a lot of information. But it's nothing compared to what else is out there. Google can only index the visible web, or searchable web. But the invisible web, or deep web, is estimated to be 500 times bigger than the searchable web. The invisible web comprises databases and results of specialty search engines that the popular search engines simply are not able to index.