The last few days I'm itching to change the distribution I'm using for years, Debian. Since stability is of major importance for me and I'm not interested in bleeding edge features, I've decided to play around with RHEL. Considering it's not free and being aware of CentOS, I've decided also to make some further investigation to the issue.While searching, I've found an interesting comment from user Christopher in this question, which says the following (among other things):Yeah... recompiled sources. But, only Red Hat has the secret sauce to compile them correctly. CentOS 6 is 85% different in terms of binary compatibility with RHEL 6.Which gave further boost to my initial wondering Red Hat is investing a lot on their OS. Can it be THAT similar with the CentOS? Is there nothing that they can do to make things a little bit more closed source? And the actual question:CentOS is considered to be binary compatible with RHEL, but what is the difference from the real thing? Is it possible by using different compile configurations to produce an entirely different OS? 
Could the compile procedure be the real difference between Red Hat EL and CentOS?
linux;centos;rhel;compiling;compatibility