Yes, AdSense is down for system maintenance for six hours today, starting at 10am PST. If you try and access AdSense, you will get an error message that it is down for maintenance.
This Saturday (7/29), we’ll be performing routine system maintenance at 10 am PDT. Although you won’t be able to access your account for approximately 6 hours, ads will still be served to your pages, and your account stats and earnings will continue to be recorded.
And yes, AdWords is down too.
But as usual, ads will contiuned to be served and stats will be tracked, although those of you who regularly check sats every fifteen minutes will be suffering from severe withdrawl when AdSense comes back up at 4pm PST.
Since both are down for such an extended period, when this happens there is usually something shiny and new for publishers or advertisers to play with when it comes back online, so there could be something new and cool at 4pm today.