"The AdWords API is designed for developers representing tech-savvy advertisers and the ecosystem of third parties, which includes SEMs, agencies, and other online marketing professionals who manage multiple client accounts and/or large campaigns," said Google spokesman Mike Mayzel in an e-mail.
The release of API doesn't in itself provide any new functionality--it simply allows developers to create programs that enhance the value of AdWords, and make their use more efficient. For instance, a marketer might create a program to integrate his own databases with AdWords data in order to trigger ads to run automatically when inventory is high.
Search engine advertisers praised the move as a step forward for the industry. "Google AdWords has always been a great interface for the individual campaign. You can upload, change bids," said Matt McMahon, Fathom Online vice president. "The automation that we're going to get out of this is really going to push forward the industry."
The use of the API system is free to AdWords subscribers, but access is limited to a certain number of activities per month, based on ad spending. Each AdWords client receives a "token," which identifies his account activity. Tokens will have a monthly quota of operations that can be performed, which is determined by the aggregate account spending of all the managed accounts. Every action--checking the status of a single ad group, for example--counts against a developer's total.
The move had been rumored for a few weeks now on industry insider sites such as SearchEngineWatch.com and SearchEngineLowdown.com, but Google declined to comment on the speculation until Friday.