As far as I know, Big G and other search engines see age of links a positive factor for ranking a page. So let's assume you gain a backlink from Digg's front page and G finds it and increase the ranking of your page. But you can't remain at the front page for a long time, and later big G revisit Digg and find your link disappears from the front page, and I guess your ranking will be discounted.. What I believe is permanent backlinks from lower PR sites is better than temporary links from high PR sites. Am I true????