Course evaluations are forms that students are asked to fill out at the end of every semester. You rate the professor, the course content, the TAs, etc., on scales of 1 to 10 or whatever. Then you have the chance to leave some comments. Increasingly course evaluations are moving online, and so students are receiving more and more annoying emails telling them to fill in the forms.
The official course evaluation process generally suffers from a reputation for being useless. It is widely believed that past results have usually either been lost, left in a corner, destroyed by flood or fire, or ignored.
However, the student councils are now suggesting the results of the evaluations might be made available to students in some marginally useful way. It's likely all we'll end up with is a little bar for each course giving it a score from 1 to 10, or something like that. The vast majority of courses will average out at something between 7.45 and 7.55. So we still won't really have anything useful to go by.
Typical student council blurb on why you should fill in course evaluations:
When registration time rolls around, we all start swapping stories about professors and classes. No one wants to wake up and head off to an 8:40am lecture that's going to be dry, boring, and a complete waste of time. That's why we have ways to review courses and professors, in an effort to shine a spotlight on the truly brilliant and fascinating members of Columbia' faculty. However, we should all remember that "one person's trash is another's treasure," and maintain some level of maturity and respect when trading classroom experiences or horror stories. This will ensure that reviews actually contain useful information instead of promoting a culture of snarky, sarcastic, and caustic memories of our time here.