1. A computer-implemented method, comprising: providing a user interface for presentation on a display device, the user interface including at least one user interface element for allowing an advertiser to specify a conversion type and associate the specified conversion type with a conversion value; receiving input specifying a conversion type and associated conversion value; and providing the advertiser with a code snippet adapted for insertion into a script for generating a conversion confirmation, the code snippet including a parameter associated with the specified conversion type, where the parameter is used by a payment system for handling a payment transaction associated with the advertiser in response to a conversion action.