http://blogs.kqed.org/mindshift/2010/12/7-important-traits-of-a-great-mobile-learning-app/

The best learning apps have the following attributes:

1) They’re interactive. Touchscreens beg for touching.

2) They’re designed for shorter playtimes.

3) They’re focused narrowly by age and relevant to what they’re learning and their motor skills.

4) They’re fun, engaging children by making them laugh — but too too much.

5) They’re inter-generational, allowing a way to involve parents.

6) They’re modifiable, giving kids options to personalize.

7) They have built-in goals, to keep kids coming back with incentives.