They are Importent, and they bring a lot power but only if you can use your Brain. I saw a lot of People actualy Building Tiered link Campaigns they built for tier 1 Some high Quality Blog Comments, Few web 2.0s, some unique Social Bookmarks, and some other kind of links. So they Built lets say 100 Links per keyword as T1 over 90 days, okey so far nothing wrong with that. But then they started Building Tier 2 Links to all these Links. They built all kind of links lets say another 200 Links to every T1 Link. This is in Theorie also fine. So now they thought okey, I build now T3 Links like a bastard and they did. They Build 500 Links per T2 Link and also I have to say, nothing wrong with that. And then they watched the Serps, They got nearly Zero Improovements. So they started telling me, that Tiered link Building is Crap and don't work anymore. So I took a look at what they did. On first view it looks fine, they have many links over differential tiers, but if you look a bit closer, turn on your Brain then you'll see that most of Tier 1 links are Nofollow links. So they wasted a lot of time and money in Building Links to Links who don't pass any linkjuice. Usually if I wouldn't tell them anything they would just keep Building T3 Links to Links that don't pass anything. So better build your links with using your brain than without, and your T3 Links will help you a lot and won't hurt your.