What is LSI / LSA and its relevance to SEO? I am confused about it. please if someone knows about it so please reply me. and also explain to me how phrase-base algorithms work? Clustering?
Latent semantic analysis (LSA) is a technique in natural language processing, in particular in vectorial semantics, of analyzing relationships between a set of documents and the terms they contain by producing a set of concepts related to the documents and terms. Latent Semantic Indexing (LSI) is an indexing and retrieval method that uses a mathematical technique called Singular Value Decomposition (SVD) to identify patterns in the relationships between the terms and concepts contained in an unstructured collection of text. LSI is based on the principle that words that are used in the same contexts tend to have similar meanings. A key feature of LSI is its ability to extract the conceptual content of a body of text by establishing associations between those terms that occur in similar contexts.
Latent Semantic Analysis(LSA) is a mathemetical method to bring out the latent relationship within a set of documents. Instead of searching each document isolatedly, it looks for the search term within all documents as a whole and terms within them to identify relationships. Through Latent Semantic Indexing(LSI) Google tries to sort out sites on the basis of frequency of variety of terms and key phrases instead of frequency of a particular keyword. The sites which focuses on a single keyword or phrase to rank that keyword will see their site's ranking going down or getting penalized as a result of over-optimization.