Wednesday, February 29, 2012

Search Engine Algorithm Basics for Onpage Optimization - Feb 2012


A good search engine tries to answer the underlying question
But only by analyzing the on-site and off-site factors is it possible for Google to determine which pages will answer is the question behind the query. For this Google will have to analyze the text on a page.
True OR False
Search engines have evolved tremendously in recent years, but at first they could only deal with Boolean operators. In simple terms, a term was included in a document or not. Something was true or false, 1 or 0. Additionally you could use the operators as AND, OR and NOT to search documents that contain multiple terms or to exclude terms.
Number of times you use a keyword term is not necessarily important. It is important to find the right balance for the keyword terms you want to rank.
An explanation of the table below:
    tf = term frequency
    df = document frequency
    idf = inverse document frequency
    Wt,q = weight for term in query
    Wt,d = weight for term in document
    Product = Wt,q * Wt,d
    Score = Sum of the products

formula for this is as follows:


The table below is a visual representation of this formula. Suppose we apply the following values ​​:
Query terms: +1 (alpha)
Relevant terms: +1 (beta)
Irrelevant terms: -0.5 (gamma)

Speed up the process
static values ​​to determine for which documents you want to calculate the score. For example PageRank is a good static value. When you first calculate the score for the pages matching the query and having an high PageRank, you have a good change to find some documents which would end up in the top 10 of the results anyway.

Relevance feedback
Relevance feedback is assigning more or less value to a term in a query, based on the relevance of a document. Their first attempt was by adding the favorite star at the search results. Now they are trying it with the Google+ button. If enough people start pushing the button at a certain result, Google will start considering the document relevant for that query.

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