7. A method for indexing advertisements in order to match an advertisement to a webpage, the method comprising: receiving click-through rate (CTR) data for an advertisement; extracting an advertisement feature from the advertisement and a webpage feature from the webpage that are relevant to each other, via a variable selection technique that includes at least one of: selection of the advertisement feature and the webpage feature using CTR data and views of the advertisement, or selection of the advertisement feature and the webpage feature using relevance scores of words of the advertisement that are independent of click feedback; calculating a coefficient representative of the relevancy between the advertisement feature and the webpage feature; computing a static score for the advertisement by using the CTR data and the coefficient as input to a logistic regression function, wherein the static score provides relevance of the advertisement feature with respect to the webpage feature, and wherein the logistic regression function uses a monotonically increasing linear function; generating a unique identification for the advertisement feature; and generating a unique advertisement identification for the advertisement according to the static score relative to other advertisements.
7. A method for indexing advertisements in order to match an advertisement to a webpage, the method comprising: receiving click-through rate (CTR) data for an advertisement; extracting an advertisement feature from the advertisement and a webpage feature from the webpage that are relevant to each other, via a variable selection technique that includes at least one of: selection of the advertisement feature and the webpage feature using CTR data and views of the advertisement, or selection of the advertisement feature and the webpage feature using relevance scores of words of the advertisement that are independent of click feedback; calculating a coefficient representative of the relevancy between the advertisement feature and the webpage feature; computing a static score for the advertisement by using the CTR data and the coefficient as input to a logistic regression function, wherein the static score provides relevance of the advertisement feature with respect to the webpage feature, and wherein the logistic regression function uses a monotonically increasing linear function; generating a unique identification for the advertisement feature; and generating a unique advertisement identification for the advertisement according to the static score relative to other advertisements. 10. The method of claim 7 , wherein the linear function is a monotonically increasing linear function, including one or more of an iterative scaling, a nonlinear conjugate gradient, a quasi-Newton, an iteratively-reweighted least squares, a truncated Newton, or a trust-region Newton function.