Abstract: A computer-implemented method for serving advertisements based on article availability includes: receiving a first keyword submitted by a user for performing a search among articles offered by a merchant; determining, using information associated with the merchant, whether the merchant offers a first article for sale that corresponds to the first keyword; and forwarding at least one advertisement in response to the first keyword, the advertisement selected without using the first keyword if the merchant offers the first article, and selected using at least the first keyword otherwise.

Abstract: Disclosed are a method and system for receiving a plurality of potential features to be added to a model having existing features. For each of the potential features, an approximate model is learned by holding values of the existing features in the model constant. The approximate model includes the model having existing features and at least the potential feature. A performance metric is computed for evaluating performance of the approximate model. The performance metric is used to rank the potential feature based on a predetermined criterion.

Abstract: Methods, apparatuses, and systems are presented for measuring difference between graphics images relating to performing an arithmetic operation involving a first graphics image comprising a plurality of first pixels and a second graphics image comprising a plurality of second pixels to produce a difference image comprising a plurality of difference pixels, generating measures of proximity from a plurality of ranges of observation within the difference image, wherein the measures of proximity represent spatial proximity of difference pixels to other difference pixels within the difference image, and applying non-uniform weighting to the difference pixels to produce a weighted difference image, wherein the non-uniform weighting depends on the measures of proximity generated from the plurality of ranges of observation.