1. A computer-implemented method to associate key phrases stored in a search engine query log to content pages, the method comprising: receiving one or more search engine query logs having search queries and content locators for search results; filtering the search engine query logs based on specified metadata, wherein the specified metadata includes at least one of location information, user information, and temporal information; generating a score for each query; augmenting a score for the query based on user interactions with content for the query, wherein the user interactions includes at least one of click-through rates, click-through patterns, and dwell times; ranking and categorizing each query in the filtered search engine query log based on the score, wherein a query is categorized as a dominant key phrase when the score is above a threshold, a seasonal key phrase when the query is present in the filtered search engine query log over a recurrent interval of time, or a stable key phrase when the query is continuously present in the filtered search engine query log over a significant period time; and storing in a content-to-key phrase index, for each key phrase, the score, corresponding content, and an indication whether the key phrase is dominant, seasonal, or stable.