I found it very interesting and I'm very keen to share this info about Microsoft MSDN2 hackable URL's.
Hackable url's are those that can be predicted by user. And yes finally the suspense is out, here goes the link,
http://msdn2.microsoft.com/library/FullyQualifiedNamespaceOfObject.aspx
For e.g., if you want to search msdn2 for help on System.Web.UI.Page then you can simply type
http://msdn2.microsoft.com/library/System.Web.UI.Page.aspx
or if you want to search for say for System.Collections.Generic then simply type
http://msdn2.microsoft.com/library/System.Collections.Generic.aspx
and so on.
happy hacking ;)