But I agree with your suggestion: NO. There's no way they'd risk blatant breaches of confidentiality like that, and given how many job searches we've all had going on in our current departments in recent years, don't you think someone who used THIS wiki would eventually get knowledge of THAT wiki and sound an alarm? There's no way such a thing exists formally.
But I'm sure it does happen that people talk across universities. I once had a job interview at university X one week and university Y the next week. The two people "hosting" me in the two places were former lab mates, and still close friends (one of them even mentioned the other in conversation), which made me really suspect that they knew I had interviewed at the other place as well and perhaps had discussed me. So maybe things are discussed, but there's no way anyone is doing this formally.