Should there be an R-beginners list?
I do not see how it can be illegal to download and duplicate the posts, since all the content is licensed under CC BY-SA. I might have missed something there: http://stackexchange.com/legal If that is really the case, I think I will have to reconsider if I should use it any more.
I'm not a lawyer, but I see claims restricting users to "personal use".
Neither am I, but I don't see any claims about personal use in the "Subscriber Content" section, which is what concerns content that other people have uploaded to stackoverflow. As Yihui says, all questions and answers (as opposed to the stuff written by stackoverflow the company) is licensed with http://creativecommons.org/licenses/by-sa/2.5/. I suspect you'll find that the mailing list is in more of a grey area since authors own the copyright to their posts and haven't agreed to any redistribution (apart from what is obvious in signing up for a mailing list). Hadley