The Google AdWords API is now supporting the Traffic Estimator Service, which provides traffic estimates (CPC, clicks per day, etc.) for new and existing keywords, according to a recent blog post. The blog post states:
AdWords API users can access our trove of historical keyword and bid data via the Traffic Estimator Service, which gives detailed estimates of how much traffic a keyword may generate at various CPC values. The service is not only useful for new products or campaigns, but it can also estimate the impact of changing the Max CPC of existing keywords as well.
Pretty cool stuff. There may be some very fun applications for this API function.
Forum discussion continues at Google Groups.