Hai, this is a 'new to be launched' feature from google. Here is the official words.. ""We're very excited to let you know about an upcoming feature that lets you easily manage your ad units from within your AdSense account. It isn't live yet, but here's a sneak peek so you'll know what to expect in the coming weeks. (We know many of you have been eagerly anticipating its arrival.)This new ad management feature means that your ad unit settings (such as colors and channels) for new AdSense for content ad units will be saved in your AdSense account every time you generate ad code. Then, if you'd like to change any of these settings in the future, all you do is make the update within your account -- you'll no longer need to manually replace the ad code on all of your pages. For instance, you can quickly change the borders of all your 300x250 medium rectangles from red to blue with just a few mouse clicks. Fancy! We hope that this new feature will help you save time and will simplify the process of optimizing your ad units.As we noted above, please keep in mind that the ad management feature isn't yet available in any publisher accounts. We'll be rolling it out in phases in the next few weeks, and we'll follow up with another post at that time to help you better understand how to use the feature. When you see the "Manage Ads" page appear under your AdSense Setup tab, you'll know the feature is available for you to use. Here's what it will look like:Stay tuned to read more about this new feature!"" I wonder whether this feature will be really helpful? Maybe to those using FREE Webhosts. coz, those with paid hosts can do this using 'Server Side Includes' or scripting (php or cgi etc) without any problem. I wonder what your comment would be on this new feature?
As you said could be a great feature for sites with cheap hosting without SSI or dynamic pages (php, perl, etc).