1. A method, comprising: generating by a network device one or more graphs using data obtained from a query log, the one or more graphs including an anticlick graph, wherein the anticlick graph represents information pertaining to documents in previously provided search results that, according to the data obtained from the query log, have not been clicked by a user that submitted a corresponding search query and does not represent information pertaining to documents in the previously provided search results that, according to the data obtained from the query log, have been clicked by the user that submitted the corresponding search query, wherein the anticlick graph includes one or more nodes representing or corresponding to documents that, according to the data obtained from the query log, have not been clicked by the user that submitted the corresponding search query; ascertaining by the network device values of one or more syntactic features of the one or more graphs; determining by the network device values of one or more semantic features of the one or more graphs by propagating categories from a web directory among nodes in each of the one or more graphs; and detecting by the network device spam hosts based upon the values of the syntactic features and the semantic features; wherein the anti-click graph includes a host-based graph or a document-based graph, wherein the nodes of the host-based graph includes one or more host nodes representing hosts corresponding to the documents that, according to the data obtained from the query log, have not been clicked by the user that submitted the corresponding search query, and wherein the nodes of the document-based graph includes one or more document nodes representing the documents that, according to the data obtained from the query log, have not been clicked by the user that submitted the corresponding search query.