[dr_who_2]

Flushes out incompetent and lazy teachers and highlights the good ones,
How a teacher performs in front of a camera tells you absolutely nothing about how good a teacher is, especially if there's no audio and the kids are trying as hard as the teacher is to look like they're paying attention.

Helps ID best practices for teacher training
Sure, hours and hours of video taped performances by professional teachers will supplement the mindless pablum they get when they're studying reeeeel hard for their teaching certificate.
Enables parental evolvement
...if your parent is kind of pillar of society that is fond of watching taped episodes of Jerry Springer.

Creates a record bad student behavior

...that will be filed away in a huge database until five years after said bad student has dropped out of school or ended up in jail for murdering another student.

[elfman2]

" How a teacher performs in front of a camera tells you absolutely nothing about how good a teacher is, especially if there's no audio and the kids are trying as hard as the teacher is to look like they're paying attention."
Why do you want to eliminate the audio? Why do you think you can't evaluate teacher performance from watching and listening to them. How can kids look like they're paying attention 6 hours a day without improving their attention?

" Sure, hours and hours of video taped performances by professional teachers will supplement the mindless pablum they get when they're studying reeeeel hard for their teaching certificate."
Sure, teaching certification couldn't possibly be improved by including a few snips for real world problems or solutions. Excuse me for suggesting that there's room for improvement.

"...if your parent is kind of pillar of society that is fond of watching taped episodes of Jerry Springer."
You do know we're discussing webcam, not just taped video right? Why would you assume that it would be Jerry Springer parents that would watch the most?

"...that will be filed away in a huge database until five years after said bad student has dropped out of school or ended up in jail for murdering another student"
Why can't you imagine the benefit of a teacher going back and snipping the part where a kid flipped her off or called her a name few hours earlier after the kid denies it?