Forgive me for asking such a simple question, I understand why you would want to rel nofollow untrusted links (forum posts, blog comments etc), but why would you not want to do it on EVERY link on your website?
I know it's greedy and perhaps unethical, but if I write a blog post and link to an interesting website within that post, am I losing out in any way by not rel nofollowing it? Is my juice leaking?