[Haskell-cafe] How unique is Unique

Hello! Lacking a proper blog, I've written some notes about Data.Unique here: http://community.haskell.org/~emax/darcs/MoreUnique/ This describes a real problem that makes Data.Unique unsuitable for implementing observable sharing. The document also proposes a solution that uses time stamps to generate symbols that are "more unique". Does anyone have any comments on the proposed solution? Are there any alternatives available? Thanks! / Emil