Google Rolls Out Site Authentication For Adsense
Google now allows you to put adsense on your private forums and website which are accessible only by logging in.
We’ve recently launched a new feature called Site Authentication to take care of this problem. Using Site Authentication, you can give our crawler access to your login-protected pages by passing it information to log into your site. For example, let’s say your news site has a premium content area, with articles that only paying members can access. To get ads on those pages, you can use Site Authentication to provide our crawler with a test username and password. It’s an easy process that starts just by logging into your AdSense account and finding the ‘Site Authentication’ link under the ‘AdSense Setup’ tab. Once you’ve supplied us with a username, password, and a few other details, all you have to do is verify that you own the site through Google Sitemaps.
They haven’t rolled this out to everyone yet.
Source: Google Adsense Blog