[noelwelsh]

This was a nice read but I'm much more interested to know what they do with the data. From hanging around "big data" people the emphasis still seems to be on storage and simple SQL-esque querying. For most people this is a solved problem, and it's time to go beyond storage and see what value we can get from data. I believe in most cases this requires a different skill set and different mindset. Most people think in binary terms, but statistical models deal with shades of grey -- nothing is ever certain -- and even simple models like linear regression are difficult for the untrained to understand.

[ZeroGravitas]

A couple of older posts about what they're doing:

How Khan Academy is using Machine Learning to Assess Student Mastery

http://david-hu.com/2011/11/02/how-khan-academy-is-using-mac...

Khan Academy: Machine Learning → Measurable Learning

http://derandomized.com/post/51729670543/khan-academy-machin...

I think the latest Dashboard design that they've just (soft-?) launched is based on this work. When you first start it asks you about 10 questions and based on your performance on that short "Maths pre-test" guesses what you know and what you don't across the whole of Maths.