1. A method, comprising: grouping a plurality of documents into a plurality of clusters using a Uniform Resource Locator-based clustering process, wherein said Uniform Resource Locator-based clustering process is based, at least in part, on one or more Uniform Resource Locator attributes for each of the plurality of documents; and minimizing the number of clusters by merging structurally similar clusters based, at least in part, on an expression-based clustering process performed over the plurality of clusters.