| last month | this month | ||
| https://www.coursera.org/ | 1,865 | 1,963 | -5% |
| https://www.udemy.com | 2,081 | 1,965 | 6% |
| http://quizlet.com/ | 4,427 | 3,530 | 20% |
| https://www.khanacademy.org/ | 4,476 | 4,168 | 7% |
| https://www.udacity.com/ | 7,042 | 6,705 | 5% |
| http://www.coursehero.com/ | 19,050 | 15,431 | 19% |
| http://learni.st/ | 26,042 | 17,779 | 32% |
| http://academicearth.org/ | 59,980 | 64,008 | -7% |
| http://openstudy.com/ | 61,018 | 48,932 | 20% |
Shao 