Google has added a new tab, a tab they have been beta testing for a couple months, named Site Diagnostics. What this tool does is show you which pages the AdSense crawler is having problems getting to. Why would they crawler have a problem getting to those pages? The several possible reasons include a robots.txt file blocking then, password protected pages, server down or slow and other reasons explained in the AdSense help pages.
I have posted screen captures at the Search Engine Roundtable.
Meet Your Favorite Search Engine Watch Contributors
Many of SEW's leading expert contributors will be at ClickZ Live, the new online and digital marketing event kicking off in New York (March 31-April 3). Hear from the likes of: Thom Craver, Josh Braaten, Lisa Barone, Simon Heseltine, Josh McCoy, Lisa Raehsler, Greg Jarboe, Dan Cristo, Joseph Kerschbaum, John Gagnon, Eric Enge and more!