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?
nofollow
was the worst thing Google have ever invented, i also commented this in Matt Cutt's article ad the Google nofollow paradox: mattcutts.com/blog/quick-comment-on-nofollow/#comment-243379