Crooked Timber, You Can be The Ethicist:
Graduate Admissions Committee for the department in question is deciding whom to admit. For said discipline, as for several others, there is a website on which potential students gossip share information about the departments to which they are applying, and many do so anonymously. However, many such students say enough about themselves that if you are in possession of their file (as graduate admissions committee is) you can identify them with near, and in some cases absolute, certainty. One applicant to said department behaves on the website (under the supposed cloak of anonymity) like… well, very badly, saying malicious things about departments he has visited, raising doubts about whether he is honest and the kind of person it would be reasonable to want other students to deal with, and generally revealing himself to be utterly unpleasant.
Question: is it wrong for the GAC to take this information about the applicant into account when making a decision? Secondary question: does it make a difference to your answer that the department is in a private, not a public, university?
My knee-jerk reaction was that one better be pretty darn sure one has the right person before making a major decision about them based on something posted on a web site.
This reaction was reinforced by one of the many very interesting comments at Crooked Timber, which asks how the committee can be sure that this wasn't a joe-job. Indeed, if it became known that this sort of attack was possible, what a way to do down one's rivals and ex-inamoratas!
I can imagine a world in which a committee might ask for further information in light of something like this, but depending on what amounts to hearsay without some sort of confirmation is, I think, a dangerous road to tread. It might even be a denial of due process in a public process.
Here's a slightly different hypothetical that may serve to test my intuition: suppose instead of a web posting that seems to be by the applicant, the committee received an unsigned letter accusing the applicant of the same bad behavior. What result, and why?