GENERATING TARGETED PAID SEARCH CAMPAIGNS

In particular embodiments, constructing a classifier based on a plurality of training keywords. Each training keyword comprises one or more words and has a corresponding training keyword document. Constructing the classifier comprises: for each training keyword of the plurality of training keywords, annotating the training keyword with one or more labels of a plurality of labels, each label having a corresponding label document; and for each label annotating the training keyword, determining a correctness of the label; calculating a first index-wise product between a word count vector of the training keyword document corresponding to the training keyword and a word count vector of the label document corresponding to the label; and forming a pair of the correctness and the first index-wise product; and training the classifier using one or more pairs of the correctness and the first index-wise product.