Methods, apparatuses, and articles of manufacture for detecting, by an
agent trusted by a merchant and a search engine, a click on an
advertisement displayed by the search engine, are described herein. The
trusted agent may further determine that a transaction of the merchant
associated with the displayed advertisement was completed and determine
whether the completed transaction was resulted from the click. In some
embodiments, the trusted agent may notify the merchant and the search
engine of a billing event associated with the click, if the completed
transaction was determined to be resulted from the click.