SEO Earnings

When you submit a query to Google, its search engine does the following

1. parse your query and extract the lexicon out of your query.
2. map your lexicon to the wordID.
3. seek the start of the document list for every word in your query.
4. scan through the doclists until a document that matches all the search terms.
5. compute the rank of each document.
6. if we are not at the end of the doclists, go back to step 4.
7. sort the documents that match the query and returns.

however, once a certain amount of the documents are found, say 40000, Google goes to the final step immediately, such that the upper bound of the response time of the serch engine can be guaranteed.

Let the things be simple, we quote an example here. For example, we will search for a single word query, say "happy", the search engine scan the doclists pointed by wordID:happy. when the search engine get the word "happy" in the document, it is weighted with a factor according to its type, like title, anchor text etc. This method is to avoid that no particular factor can have much influence to the result.

Finally the above score is combined with the PageRank calculated from the Links to form the final result.

For multiple word query, it is much more complicated that what we think, beside each type-weighted factor, it has a word proximity weighted factor in consideration. Actually, these parameters are the real mystery behind Google, and it is expected changing all the time to adapt changes.