Folks.... there is more than one algorithm used in the scoring of documents. Think of it like layers of an onion (canse the SERPs make U cry..he he) There are a varety of methods used and each can be assigned it's own weight in the over-all process depending on the thresholds set for each... Some core areas are; Links (nodal popularity) Relevance User performance metrics Similarity ( duplicate content filters) Authority There are many methods related to the above concepts and each is added into the process and weighted via thresholds. There is no simple 'Google Algorithm'