[graeme]

The chance to make a meaningful impact in people's lives.

Sal Khan and Sebastian Thrun both commented on the letters I support they received. Many people were deeply appreciative - and they were often outside of the typical university demographic. Single mothers, the unemployed, people switching careers, third world students, those who never got the material using traditional methods all told them how their efforts changed their lives.

These teachers are already materially successful. Their work was intellectually stimulating. But this type of feedback was something new for them. They could help thousands of people. It's very hard to ignore that possibility, and go back to your day job.

I have no doubt that Agarwal has already had similar feedback from MITx. He likely had no choice but to fully commit to it.

PG recently commented that moving YC to silicon valley was both the ambitious choice and the self indulgent choice. That's an irresistible combination, and these professors are in the same situation. They can be push their field forward with the knowledge that their are deeply impacting the lives of thousands of fellow human beings.