6. A method comprising: under control of one or more processors configured with executable instructions, establishing a model for regularization, the model being established, at least in part, by: sorting a set of training web pages into a plurality of labeled groups based at least in part on user behavior information with respect to the training web pages; and establishing one or more hierarchical relationships between the plurality of labeled groups based at least in part on a determined relative priority of each labeled group for inclusion in an index, the one or more hierarchical relationships between the plurality of labeled groups including at least one hierarchical relationship between a first labeled group of the plurality of labeled groups and a second labeled group of the plurality of labeled groups; receiving a plurality of crawled web pages; and applying regularization based at least in part on the model to select a subset of the crawled web pages for indexing based at least in part on: user behavior information with respect to at least some of the crawled web pages; features extracted from the crawled web pages; and link relationships between the crawled web pages.
6. A method comprising: under control of one or more processors configured with executable instructions, establishing a model for regularization, the model being established, at least in part, by: sorting a set of training web pages into a plurality of labeled groups based at least in part on user behavior information with respect to the training web pages; and establishing one or more hierarchical relationships between the plurality of labeled groups based at least in part on a determined relative priority of each labeled group for inclusion in an index, the one or more hierarchical relationships between the plurality of labeled groups including at least one hierarchical relationship between a first labeled group of the plurality of labeled groups and a second labeled group of the plurality of labeled groups; receiving a plurality of crawled web pages; and applying regularization based at least in part on the model to select a subset of the crawled web pages for indexing based at least in part on: user behavior information with respect to at least some of the crawled web pages; features extracted from the crawled web pages; and link relationships between the crawled web pages. 20. The method according to claim 6 , the one or more hierarchical relationships established between the plurality of labeled groups further including at least one hierarchical relationship between one of: the first labeled group of the plurality of labeled groups and a third labeled group of the plurality of labeled groups; or the second labeled group of the plurality of labeled groups and a third labeled group of the plurality of labeled groups.