http://quantifiedself.com/2011/09/roger-craig-on-knowledge-tracking/#comment-3004

Also from Final Jeopardy: Man Vs. Machine and the Quest to Know Everything, by Stephen Baker, pg 214:

"The program he put together tested him on categories, gauged his strengths (sciences, NFL football) and weaknesses (fashion, Broadway shows), and then directed him toward the preparation most likely to pay off in his own match. To patch these holes in his knowledge, Craig used a free online tool called Anki, which provides electronic flash cards for hundreds of fields of study, from Japanese vocabulary to European monarchs. The program, in Craig's words, is based on psychological research on 'the forgetting curve'. It helps people find holes in their knowledge and determines how often they need those areas to be reviewed to keep them in mind. In going over world capitals, for example, the system learns quickly that a user like Craig knows London, Paris, and Rome, so it might spend more time reinforcing the capital of, say, Kazakhstan. (And what would be the Kazakh capital? 'Astana', Craig said in a flash. 'It used to be Almaty, but they moved it.')