Self-learning online has become very popular and there are several sites offering courses to learn a wide range of topics. For a project I needed to get an overview of some of the most popular sites and created the below matrix. Here it is for all of you to read, please let me know if you find something incorrect. Of course this is not a complete listing of all such sites, Futurelearn and iversity among others were left out, but the table still contains the biggest ones.
|Coursera||edX|| Khan |
|Cost||Free||Free||Free||$20-$35 per month||Free to $10 per month||$25-$49 per month||Free to $300 per course|
|Course completion certificate||Paid||Paid||No||Yes||No||No||Yes|
|Type (mooc, etc.)||MOOC||MOOC||Video library||Video library||Video library||Video library||Video library|
|Users||10 million||4 million||10 million||4 million||0.9 million||0.1 million||8 million|
|Mobile apps||Android and iOS||Android and iOS||Android and iOS||Android, iOS and Windows||Android and iOS||Android and iOS||Android and iOS|