10. The method of claim 5 wherein outputting the indication of the quality of the web page comprises outputting an indication of the binary classification of the web page.
5. A computer-implemented method for classifying a web page, comprising: accessing, by one or more computing devices, local web page information of and global web graph information about a plurality of authoritative web pages, local web page information of and global web graph information about a plurality of non-authoritative web pages, and local web page information of and global web graph information about the web page, wherein: each authoritative web page of the plurality of authoritative web pages is a web page of known high quality, each non-authoritative web page of the plurality of non-authoritative web pages is a web page of known low quality, the local web page information of the web pages comprises text, clicking, domain, or time stamp information concerning the web pages, and the global web graph information about the web pages comprises hyperlink or co-citation relationships among the web pages; determining, by the one or more computing devices, a quality of the web page using collective inference by applying collective inference for binary classification of the web page using the local web page information of the web page and the global web graph information about the web page, the local web page information of the plurality of authoritative web pages and the global web graph information about the plurality of authoritative web pages, and the local web page information of the plurality of non-authoritative web pages and the global web graph information about the plurality of non-authoritative web pages, comprising finding a minimum value of a regularized convex dual of a logistic regression loss function for a node of a graph; and outputting, by the one or more computing devices, an indication of the quality of the web page.