Google uses PageRank (PR) to evaluate how relative content is -- how good your hits are when you do a search.
It calculates this by using the number of people who link to you, what they write in the link text, and how popular those who are linking to you are.
This means that if A, B and C are all very popular and link to you, you get more google juice. In other words, linkpop.
How canny.
Internet marketing has a new hero, and his name is refer spam.