In the past 2 years, a very important factor in web content writing was keyword density, with the recommended 2 to 7% agreed by most seo experts. Well, that has changed for 2007, at least as far as Google goes. Their new patent clearly indicates the massive role that Latent Semantic Indexing is going to play in how they evaluate the relevancy of any given page and therefore its rank by closely considering co-occurrence rates and semantically related phrases, especially focusing the attention on the first one.