You have a good point about people already being motivated to do something if they're looking for an app. However, "wanting" to do something tends to be a short-term motivation as compared to the grittier, determined motivation of "doing" something. For example, in my experience with my sister when she wanted to learn foreign languages in her spare time, she started off very motivated and we got all the right resources and "tools". However, when the "honeymoon" period of motivation wears off, it becomes difficult to keep going at it until you reach that stable sweet spot called "habit".

Though I referenced "motivation" earlier for simplicity, the underlying psychological mechanics I want to build in are much more complex than motivation. I've been researching an interesting cross-disciplinary domain between psychology and technology and have learned that it IS possible to use computer or mobile devices to motivate and shape the habits of a person. For the actual implementation of that, I'm still tweaking it around, but will hopefully be able to have some experiments out by this summer or fall. Of course, I could always try the faster route and find someone else to build the app for me, but I like programming enough that I want to achieve the self-satisfaction of building the first prototype at least.

(A semi-success story. After the past 2 years of tweaking and examining our assumptions, my sister and I have successfully designed a self-sustaining system that keeps her engaged in what she wants to learn...on a 10-hour daily schedule, she's learning 3 languages, music and other subjects without supervision (she's 15). It's more rigorous than her high school curriculum but it's amazing how lighting-speed she learns when she's in this state of flow everyday. Now hopefully what I've learned from this can be applied to many other people too.)