Any type of Pyramid link building scheme is considered black hat and punishable by Google's Link Spam Updates AKA - Google Penguin.
The idea of using a 2 and 3 tier system was that you could spam some low quality links to the tier 3 and then dribble it down to the 2nd and then to the main site (Money Site) and the money site would not be punished since they would only have a couple of incoming links with the weight of 10,000s and 100,000's being dripped from Tier 2 and 3 sites.
Google isn't stupid and is forever improving their engine to detect such schemes and the simple Pyramid T2 and T3 system has been detectable for some time. We now have people using 10 tiers upwards but this again leaves a footprint and Google has said this year we can expect the biggest Penguin update which is going to shake the world and black hatters upside down.
Build great content
Rather than spending time on systems that are likely to get you punished at a later date as MILLIONS have already and its worth noting that less than 1% come back after being hit by penguin. You are better of creating good content and getting back links the natural way for a long term strat... Black hat today is now considered a Quick Win, then lose.