[CentOS] how is "binary compatibility" determined?

>> 
>> 
>> Thanks Keith, good question, that should have been on my list of
>> "Questions to ask about CentOS building process", and thanks to Akemi
>> for a quick answer :)
> 
> Given that its answered in a FAQ one could argue that it was not a good
> question.

You know, there is a famous saying.. "If you have nothing nice to say, don't say anything at all".