12. The system recited in claim 10 , wherein the random walk analysis is terminated based on a hitting time analysis.
10. A system for improving the quality of search results, comprising: a processing unit; and a system memory, wherein the system memory comprises code configured to direct the processing unit to: determine whether to reformulate a user query to a search engine based on a relationship between a user search term in the user query and a graphed search term represented in a graph having nodes that represent search terms of previous user queries and edges representing relationships between previous search terms, and each of the nodes comprising a n-gram, the decision to reformulate the user query taking into account the relationship between the user search term and the graphed search term, the relationship being based in part on a result of a random walk analysis on multiple edge types between two of the nodes to quantify relationships between nodes of the graph; wherein performing the random walk analysis comprises: generating parallel corpora of paired phrases based on a plurality of different fields comprising a plurality of content fields and one or more a popularity fields such that a plurality of edge types occur between at least two nodes; extracting a plurality of aligned n-grams based on alignment probabilities between different n-grams; generating the edges between the aligned n-grams based on the alignment probability of each corresponding edge type.