1. A method for classifying ads automatically in a taxonomy of categories, the method comprising steps of: extracting text features from ad images using optical character recognition (OCR) techniques; identifying objects of interest from ad images using object detection and recognition techniques in computer vision; extracting text features from the web-page of the advertiser that the user is redirected to when clicking the ad; training statistical models using the extracted features as well as the advertiser attributes from a historical dataset of ads labeled by human editors; and determining the relevant categories of unlabeled ads using the trained models.