Quoting Adam Wight and Bawolff here to be able to find their notes again later:
++the EFF for more ideas, they are actively doing great work on so-called
perfect forward secrecy.
There are simple things we could do to achieve a better balance between
privacy and sockpantsing, such as cryptolog , in which IP addresses are
hashed using a salt that changes every day. In theory, nobody can reverse
the function to reveal the IP, but you can still correlate all of an
address's edits for the day, week, or whatever, making CheckUser possible.
IP range blocking obviously needs to happen up-front, before the IP is
mangled. I have no suggestions, but maybe browser and preferences
fingerprinting would be more effective anyway, since: tor.
The cryptolog approach - This has the property that there's a specific
time where all anon identifiers suddenly change (e.g. Midnight every
day in the setup cryptolog uses). Having an arbitrary point in time
where suddenly identifiers shift is probably an unwanted property.
(Although maybe it doesn't matter that much in practice? Someone who
actually deals with abuse on wiki would be better able to answer