Leng Leng Tan announced in her presentation yesterday, that
patchset 10.2.0.4 which will be available very soon!!! 
which will allow to mask sensitive data in a captured workload 
so it is not possible to read the data in plain in the testing environment, but still run the workload for testing anyway. This will definitively make it more attractive for a number of customers to use Database Replay, one of the Real Application Testing (RAT) features in 11g.
Also it will be possible to capture a workload on a 10.2.0.4 database and run it on an 11g database for testing!!!
That’s great news – being able to record in 10.2.0.4 and replay on 11g. We’ll be able to use this feature for the migration to 11g and not wait until we are all upgraded before we start using it.
In retrospect – I should have asked the RAT people on the demo grounds who decided on this awful acronym.