QUOTE(Wikitaka @ Fri 16th March 2012, 11:44am)
It remains a mystery how this top secret tool is used. The users involved have access to the IPs of all WP users, no matter how constructive they are or how high the level of suspicion is. A wiki/mailing list only visible to CUs also exists. where personal information about innocent users is stored and discussed.
The appointment procedure is also highly confidential, but from what I know the ArbCom will make a "public" announcement, which is coordinated to be published when the users the ArbCom "want" accept an "invite".
Reviewers, I invite you to investigate the truth behind the CU process, how "fair" the appointment procedure is and the way the CIA of Wikipedia secretly discuss (and almost certainly harass) WP users. This is a real big, bad, "dark area" of WP.
In recent years (since 2009) Arbcom starts the process by widely advertising that they are seeking additional Oversighters and Checkusers. I could give a long spiel justifying the selection process, but that is missing the more important point. Since 2009 OS and CU are subjected to centralised community scrutiny before appointment, and there is an audit committee which reviews how these tools are being used. If you have a problem with how the tools are being used, go talk to them.
Checkusers do not have unfettered access to all IPs of all users. They dont watch Wikipedia like the Matrix. They need to explicitly request a small sample of this information, and that request is logged, and they are only permitted to request the data when it helps identity a problem.
The checkuser-l mailing list is almost exclusively used for coordination between projects to prevent cross wiki spammers and vandals. I have to say 'almost' as there is the occasional thread which isn't, but those threads are stomped on quickly. It is very rare (once a year, or longer) that an 'innocent' user is mentioned on checkuser-l.
The real juicy stuff happens on the functionaries-en mailing list.
However, for comparison, it is less juicy than the arbcom-l mailing list.
I'll be happy to answer any questions you might have.