1. Interesting Pivot & Unpivot feature available for year wise, monthwise ananlysis

http://www.oracle.com/technology/pub/articles/oracle-database-11g-top-features/11g-pivot.html

2. Deduplication features is immediate requirement for document management, where we are storing same kind of documents in different places like booking, job, payment request etc – this will keep only one copy in the database and pointer in other places to link the source file

3. SQL Result cache – this will be useful like small reference tables like segment_master, service_type, currency_master etc. The same can be used for frequently accessed tables like currency_rate_master, so overhead will not be there like Disk I/O etc. This is like another type of memory area like SGA, buffer cache, PGA