PBLs are accelerated backlinks they take their extra power by the method in which they are connected with other PBLs which magnified  each other to create a powerful effect. Similar to several fright-train locomotives tie-up together to create  a much needed power to move a big cargo train. so are the PBLs  they are links on steroids

PBLs are optimized quality links (different than optimized website) that work together to achieve top placement on serp. Like enriched uranium or concentrated laser-beam it produces much greater results when optimized.    

The concept behind the PBLs is not new, many good SEOs have been using it knowingly or unknowingly. What's new is the  the systematic application of the concept to bring any keyword or phrase to be placed on top position  of serp quickly and for fraction of the cost and man-hours normally required to acquire quality backlinks.

The exact method used is being kept confidential however it is 100% white hat. and the result are long lasting. 

The PBL prove itself times and times again without fail. It is not just a theory it a practical method to get websites to top position on Google  for any keywords