If enough people use it, we could let people sell knowledge content through us.
Teachers have the incentive of making open source to get more students.
Students pay when they want help to learn something.
We take a cut of the transactions.
However this goes a bit against our "open content" ideal.
Forced sponsorware would be a possibility.
Would be a bit like Fiverr. Hmmm, maybe this is not a good thing ;-)