As you create systems that use the AdWords API to automate the creation and modification of campaigns, ads that target specific keywords, and keywords themselves, it's important to know how these created keywords are likely to perform. If you have good reason to believe that a keyword will not deliver many impressions, or if the keyword will produce a low click-through rate (CTR), your system should not target the keyword. Conversely, if a high cost per click (CPC) is estimated for a keyword, your system might decide not to run the keyword, or to assign a low maximum CPC to the keyword.
The KeywordEstimatorService AdWords API web service provides keyword traffic estimates for new or existing keywords, ad groups, and campaigns. This chapter shows you how to use the service in a simple way to get a traffic estimate for a keyword, assuming a broad match, and taking into account a maximum CPC specified along with the keyword. In a "real" application that integrated with the AdWords API, these results could be used as the basis for deciding whether to target a keyword.