GREAT EXPECTATIONS: As any celebrity will tell you, being in the spotlight draws not only eyeballs--but scrutiny. And Khan Academy, with tens of millions of "students" across the globe, knows that all too well. Last week it found itself in the crosshairs once again in an "open letter" from Christopher Danielson, a community college math teacher. His point of contention: the misleading representation of decimal place values in one of Khan's videos. The post generated quite a bit of buzz in places like Hacker News. To Khan's credit, it's employees responded in force and reiterated their commitment to engaging in dialogue and feedback. As "Ben" writes: