As an aside, I note that there is an ongoing discussion on Foundation-L about whether or not to allow Google to crawl their archives. It seems there is considerable concern about the fact Google has, in the past, highly ranked arcane and incidental discussions and thus the list does not permit robots.txt harvesting; early responses are that the membership of that list does not wish to change it, pointing out that anyone who wants to read the archives is welcome to do so, or even to participate by signing up for the list.
Risker