There are no “secrets”.
At least, there are no secrets involved in making a database perform properly. Occasionally a useful new piece of information is uncovered – and if it’s worth knowing it will be documented, discussed, and validated in public. (It won’t necessarily be documented on Metalink, OTN, or any other official Oracle site – but that doesn’t make it a secret.)
Whenever I’ve seen people doing presentations about “secrets” they’ve usually split their time between quoting the documentation, stating the obvious, making mistakes, and offering sweeping generalisations that needed careful justification.
I have a simple rule of thumb for presentations – the more glamorous, trendy or exciting the title sounds the less likely it is that the presentation will be useful (but that won’t stop me reading the abstract – just in case).