Forget about distributions, names, etc. Imagine you have a software that is critical to your business. You tested it on a specific version of an OS. Continued s

Forget about distributions, names, etc. Imagine you have a software that is critical to your business. You tested it on a specific version of an OS. Continued support means that you can keep using that OS and your software will very likely continue running on the OS without problems, and if there is something broken by a patch, then you can go and complain to them. If your software runs on Ubuntu 7.04, you suddenly upgrade to 13.10 and your software stops working, then I don't think Canonical will take any responsibility or help you. I know MS is not perfect in this either, and SP2 introduced quite significant changes, but fundamentally it's the same OS, same look, same UI paradigms, etc.; and they at least intended to keep themselves to the rules described above.