Good question. :-) My answer turned out to be a bit long, so I just created a post: http://news.ycombinator.com/item?id=485701 http://news.ycombinator.com/ite

Good question. :-) My answer turned out to be a bit long, so I just created a post: http://news.ycombinator.com/item?id=485701 http://news.ycombinator.com/item?id=485701