1. User
2. What is an "open" learning tool?
3. Output
4. other Tools
5. Input
6. Interoperability
7. Versatility
8. Usability
9. Platform/device dependency
   1. Unix
   2. Android
   3. iOS
   4. Mac X
   5. Windows
10. License
11. Source code
    1. Auditability
    2. Fixability
    3. Customizability
12. Price
    1. Trial version
       1. Trial period