As expected, Google has added dayparting capabilities for advertisers worldwide after having made a major AdWords infrastructure change - "a bit like changing the engines on a jet while you're flying," according to Richard Holden, director of product management at Google, ClickZ writes. Google's "ad scheduling," is available today in the AdWords campaign management interface.

According to a AdWords blog post, "Ad scheduling (also known as 'dayparting') lets you tell Google exactly when you want your ads to run, and more importantly - when you do not want them to run. In addition, more advanced users can automatically modify their bids based on time-of-day and day-of-week cycles in campaign performance."

Dayparting via AdWords has been available through third-party vendors using Google's API (application programming interface); according to Kevin Lee, executive chairman and cofounder of Did-It, a third-party provider can help an advertiser make the best choices: "Doing dayparting badly is as bad or worse than not doing it at all."

"Ad scheduling can…help you improve your ROI by ensuring that your ads run when it makes the most business sense. For instance, a local business may only want to run their ads during business hours, or an online retailer may want to boost their bids during their busier-than-normal lunchtime shopping period," according to the AdWords blog.

Advertisers can already use dayparting on Microsoft's adCenter, and Yahoo is expected to offer it as well.