the amount of revenue generated for a given user 39 s query by producing a ranked list of available sponsored links in one embodiment of the invention the real time user model is used to re rank sponsored links in the same manner that is used to re rank organic results the subordinate keywords are matched with the titles snippets and urls of the available sponsored links for a given query and the order of the sponsored links is changed to illustrate how this might work table ii is a representation of sponsored links returned for a user 39 s query for u201c digital camera u201d the rpc represents the amount of money that the advertiser is willing to pay for a click while the ctr represents the rate at which users click the advertisement when it is displayed on the search page the ctr will most certainly be a function of where the advertisement is displayed in relation to the others but for purposes of this illustration consider the ctr to be normalized u201c digital camera u201d ranked by the search engine as a function of as can be seen the advertisements are produced in a certain order which can be a function of many different things but typically will rely heavily on rpc and ctr this is because.