I recall (from my overpriced and underutilized psychology degree) that there is some pretty good tests to determnine how people learn... Some people absorb better when listening, some by reading, some people are haptic (hands-on), etc. I think that the challenge is understanding each user enough to be able to personalize the presentation/learning style.

Telling me I need to take 10 minutes of tests for a site to be able to provide value isn't going to be an easy sell.