NOT TO BE FLIPPANT: We're fascinated by the growing debate on the "flipped classroom" model, where students watch lectures at home and do teacher-guided homework at school. Fans are exuberant. Skeptics raise the "digital divide" issue: we can't take for granted that everyone has the hardware and networking gear to stream videos. (That's led Microsoft, Comcast, Best Buy, and others working with the FCC's Connect to Compete initiative to try to bridge the gap.) Then there are the critics: Education blogger Frank Noschese worries about the excessive marketing hype around Khan and warns against the rebirth of the "filmstrip teacher", "...except that the students just watch the filmstrip at home." Liz Dwyer from GOOD asks whether a video is more active or engaging than reading a textbook. Who's to say that students are paying attention--or just chattering away on Facebook? (This latest study from Rey Junco suggests this is where they spend on average 106 minutes a day.) Even earning "badges" for working through problem sets is tricky, as students using Khan Academy in Los Altos schools are learning.