If you are seeking high ranks with Google, it will help to know what Google is thinking.
Here’s an excellent resource on Google’s Algorithm and ranking factors: http://www.seomoz.org/article/search-ranking-factors#f41. Search Engine Optimization experts talk about their experiences with Google and express their opinions about how they think Google considers (assigns importance to) certain factors related to a website like: Quality and Quantity of Inbound links, Text Surrounding Links, Topical Relationship of Linked-To website, etc.