Google has launched a blog to help publishers understand the inner workings of AdSense; the move comes as the search giant is confronted by direct competition from Yahoo's Publisher Network and pressure from publishers to make AdSense less more transparent. In the battle between Google and Yahoo, "the advantage will go to whichever company can produce the highest effective CPMs for publishers," writes ClickZ.

The "Inside Adsense" blog (adsense.blogspot.com) will offer optimization tips and feature descriptions to prospective and existing publishers in the AdSense network, with up to three posts a week by AdSense "engineers, product managers, product marketing managers, and operations staff." Google's AdWords for advertisers has had its own blog since May.

Yahoo's contextual ad network launch earlier this month began what is likely to be an ongoing battle between the two search giants to improve both their offerings and their customer service.