How effective is checkuser? Options

[Ather]

If I wanted to run several accounts how likely is checkuser to pick me up? If I changed my IP each time I logged on how would they trap me? How long to they log IP addresses for? Do they keep a permanent record of my account creation IP? Do they record me logging on but not editing? What other info do they store and for how long? All this info is needed purely for research purposes

[anthony]

If I wanted to run several accounts how likely is checkuser to pick me up? If I changed my IP each time I logged on how would they trap me? How long to they log IP addresses for? Do they keep a permanent record of my account creation IP? Do they record me logging on but not editing? What other info do they store and for how long? All this info is needed purely for research purposes

I wouldn't count on any information you receive here about checkuser to be accurate. The checkusers have lied in the past about what sorts of checks they have done, who they have checked, how long they were storing results, etc.

[Krimpet]

I wouldn't count on any information you receive here about checkuser to be accurate. The checkusers have lied in the past about what sorts of checks they have done, who they have checked, how long they were storing results, etc.

Well, the actual code running on the servers is open to inspection, so the actual capabilities are a matter of public record.

The changelogs to the CheckUser extension are an interesting read. For example, an enwiki checkuser (Voice of All (T-C-L-K-R-D) ) tried in mid-2008 to quietly increase the retention time from three months (what it is currently) to five months, only to be overridden later by the WMF's Tim Starling with the sharply worded:

Revert change to $wgCUDMaxAge. If you want such a policy change, have an open discussion about it, don't get together with some troll-hunting mates on a private mailing list and make your own rules.

Earlier that year, VoiceOfAll was also very eager to add a pen register for e-mails sent through the Special:Emailuser interface - his first attempt at the feature was overruled by Brion Vibber with the reasoning:

Disable email logging for now -- violates our present privacy policy by logging information that we currently say is kept private (email addresses) as well as information we don't mention but which feel very creepy to log for checkuser view (subject line of mails and times and targets of private mails)

The feature was eventually greenlighted only after it was modified to not record subject lines, and to hash usernames in a way only sysadmins with database access could decipher.