University policy of publishing student course evaluations: Prevalence and pros and cons
I used to adjunct at a strong college as part of a larger university where the student government was able to get a policy in place on publishing (statistics on) evaluations.  The professor/adjunct had the choice to not publish their results; but this was uncommon since then you would be an outlier and it would seem like you had something to hide.  


Pros:  Frankly, with things like "rate my professor" out there, I'd rather have everyone's evaluations take into account than just the extremes.  I think the point is that, provided we avoid the cons I will outline, there is transparency of some sort of metric of performance.  Generally I found the statistics to show something reliable about professors based on what other faculty and students said about them.  It prevents faculty from thinking they can just disregard the opinions of their students and it helps students have a consistent and official place to decide which instructor they would like to teach them (in a larger college anyway).
Cons:  You need not look far to see academics complain about this practice.  The only concern for me would be if for some reason there was some sort of plot to purposely bomb a professor's evaluations or a professor tried to game the system; these are generally not serious worries and one would hope there would be checks and balances for these concerns.