Erik, Thanks for re-starting this thread!
It seems there are two main questions:
What would be the uses of readership data in the various forms that are potentially available? -and- How could privacy concerns best be balanced and addressed in the context of those potential uses?
I have access, for starters, to .2TB of disk that could be devoted to readership data; it seems storage and other technical hurdles could be overcome if there is consensus about what data the community wants stored, with what privacy guarantees, to what end.
There's some discussion of these questions at http://en.wikipedia.org/wiki/Wikipedia:WikiProject_Wikidemia/Quant/Readershi... http://en.wikipedia.org/wiki/Wikipedia:WikiProject_Wikidemia/Quant/Security, and further contributions to these pages would be more than welcome; the Thursday afternoon session at Hacking Days (ie, a week from tomorrow) will hopefully press forward to some (at least interim) solution.
Jeremy