select * from DBA_FEATURE_USAGE_STATISTICS ;

Want to know what has been done on your database during audit time, here is some more handy hints for working it out:

select * from DBA_FEATURE_USAGE_STATISTICS ;

Another example of when you are trying to audit what a client is using so that you can replicate this functionality.  My use case is moving someone to RDS in AWS and I want to ensure that the database features are mapped appropriately.

NAME	DETECTED_USAGES	CURRENTLY_USED	VERSION
----------------------------------------------------------------	----------------------	--------------	-----------------
ADDM	1	TRUE	11.2.0.4.0
AWR Report	1	TRUE	11.2.0.4.0
Audit Options	65	TRUE	11.2.0.4.0
Automatic Maintenance - Optimizer Statistics Gathering	3	FALSE	11.2.0.4.0
Automatic Maintenance - SQL Tuning Advisor	65	TRUE	11.2.0.4.0
Automatic Maintenance - Space Advisor	65	TRUE	11.2.0.4.0
Automatic SGA Tuning	2	FALSE	11.2.0.4.0
Automatic SQL Execution Memory	65	TRUE	11.2.0.4.0
Automatic SQL Tuning Advisor	64	TRUE	11.2.0.4.0
Automatic Segment Space Management (system)	65	TRUE	11.2.0.4.0
Automatic Segment Space Management (user)	64	TRUE	11.2.0.4.0
Automatic Undo Management	65	TRUE	11.2.0.4.0
Character Set	65	TRUE	11.2.0.4.0
Deferred Segment Creation	65	TRUE	11.2.0.4.0
EM Performance Page	1	TRUE	11.2.0.4.0
Extensibility	62	TRUE	11.2.0.4.0
LOB	64	TRUE	11.2.0.4.0
Locally Managed Tablespaces (system)	65	TRUE	11.2.0.4.0
Locally Managed Tablespaces (user)	65	TRUE	11.2.0.4.0
Logfile Multiplexing	65	TRUE	11.2.0.4.0
Object	62	TRUE	11.2.0.4.0
Oracle Java Virtual Machine (system)	65	TRUE	11.2.0.4.0
Oracle Java Virtual Machine (user)	62	TRUE	11.2.0.4.0
Oracle Utility Datapump (Export)	4	FALSE	11.2.0.4.0
Oracle Utility Metadata API	6	FALSE	11.2.0.4.0
Partitioning (system)	65	TRUE	11.2.0.4.0
Result Cache	64	TRUE	11.2.0.4.0
SecureFiles (system)	65	TRUE	11.2.0.4.0
SecureFiles (user)	65	TRUE	11.2.0.4.0
Server Parameter File	65	TRUE	11.2.0.4.0
Streams (user)	62	TRUE	11.2.0.4.0
Virtual Private Database (VPD)	65	TRUE	11.2.0.4.0