Improved PL/SQL stored procedure invalidation mechanism - A new 11g features will be fine grained dependency tracking, reducing the number of objects which become invalid as a result of DDL.
In previous releases, object dependencies were managed at the object level, so altering an object automatically invalidated all dependent objects. Oracle 11g has more granular dependency management, so only changes that directly affect an object will cause an invalidation.
http://www.oracle-base.com/articles/11g/EnhancedFinerGrainedDependencyManagement_11gR1.php
http://www.oraclebrains.com/2007/09/plsql-fine-grained-dependency-tracking/
http://ocpdba.wordpress.com/2009/03/05/a-new-paradigm-oracle-11gs-feature-for-context-objects-invalidation-coi/