A number of people are reporting that Google has implemented an AdWords Campaign Optimizer tool. We were first alerted to this on the Search Engine Roundtable Forums, where PPCblogger kindly provided us with some detailed screenshots of the tool in action.
For now, this appears to be available to select UK advertisers, as I was unable to find it in my AdWords campaigns nor was I able to find any Google US help pages on the feature. The Google AdWords Help Center (UK only) says that the goal of the tool is to fine tune your advertising campaign.
The Campaign Optimizer is a free AdWords tool designed to help you fine-tune your advertising campaigns. When you run the Campaign Optimizer, we automatically analyze your budget, keywords, and landing page, and create a customized proposal for your campaign. You can then review the proposed changes and accept the ones you want to apply.You can reach the Campaign Optimizer via the Optimize Campaign link on your campaign details page. You can also go to the Tools page of the Campaign Management tab and click Campaign Optimizer.
Included within the campaign optimizer are keyword recommendations, advertisement recommendations, and data related to when users last ran the tool.
I'm not sure if this is being rolled out to all of the UK advertisers at once at the moment, but initial reports of the availability of the tool are coming from there.
Forum discussion continues at Search Engine Roundtable Forums.
Update: Jeremy Mayes reports that this is available to US advertisers and points us to Google Help pages explaining what the optimizer does and how often it can be used.