1. A method for behavioral targeting comprising: receiving, by a processor, a plurality of events generated by a user; classifying, by the processor, each of the plurality of received events in one of a plurality of categories; selecting, by the processor as each of the plurality of events is received, a model from a plurality of models based on a marketing objective, the selected model comprising rules used for dimension processing; applying, by the processor upon the selection, the rules of the selected model to user data comprising at least the plurality of received events for determining interest of the user in the plurality of categories into which the plurality of received events are classified; generating, by the processor, a plurality of short-term raw user interest scores of the user for the plurality of categories into which the plurality of received events are classified via the application of the rules, wherein the short-term raw user interest scores are indicative of short-term interest of the user in the plurality of categories into which the plurality of received events are classified; and communicating, by the processor to an advertising server, the short-term raw user interest scores for enabling serving advertisements for small purchases customized to the short term interests of the user, the small purchases comprising purchases made in a pre-defined period of time.