There was a post on Metafilter about types of errors (maybe in response to an Ask? Although perhaps I found it in a reply to a post like this one, on MeTa?) and it had a taxonomy of errors relating to whether people would remember the error in 100 yrs time, whether it would leave a permanent mark in the fossil record, etc. I found it both funny and useful and find myself thinking of it often, but I've tried to search for it various times without luck. Does anyone know what I'm talking about?