The official wording about the program:
The Oracle ACE Program is designed to recognize and reward Oracle customers for advocating Oracle Technology and Applications. Oracle ACE recipients are chosen based on their significant contributions to, and activity in, their respective community. The program currently has two levels: Oracle ACE and Oracle ACE Director.
(Source: Oracle ACE Program FAQ)
Oracle ACEs and Oracle ACE Directors are known for their strong credentials as Oracle community enthusiasts and advocates, with candidates nominated by anyone in the Oracle Technology and Applications communities. The program comprises two levels: Oracle ACE and Oracle ACE Director. The ACE () designation is Oracle's way of saying "thank you". This is to honor the efforts of community contributors. A "thank you" both from Oracle and the community (OTN) to let them know, that they appreciate their enthusiasm.
The ACE Director () designation is for community enthusiasts who not only share their knowledge, but also want to increase their community advocacy and work more proactively with Oracle to find opportunities for the same.
A fellow ACE Director Debra Lilley caught the point like this:
I believe, and I stress this is my understanding that the ACE program has 2 sides to it. You must be a leading expert in your area AND you must contribute it sharing that knowledge, through speaking at conferences, participating in forums, authoring of books etc. Just because you are an expert in an area is NOT enough.
You can find an ACE by looking at the ACE Finder. At the time writing this, there are 230 listed ACEs and ACE Directors.
Beeing a BEA Technical Director since 2005 I was asked to join the ACE Director Team in 2008 after the Oracle/BEA merger. It is an honor for me to be part of the ACEs. So many great people, thoughts and ideas together in one place is always very inspiring. I had the pleasure to talk to some in person and they are all real people which work hard on real world solutions for their real world customer problems. If you come across one of us, don't stop asking questions. We are here with some answers!
Links around the ACEs: