Content management is a great way of improving efficiencies by shifting as much mundane processing work as possible to the dumb computer, which will work all night like a slave for no money. Unfortunately, the system is only as good as those who configure it: It can only do what it is told. So it is worth noting a few of the things that a CMS cannot do for you:

• It does not automatically organize your content for you. It certainly gives you the tools to help you structure and organize your content and will then happily manage and publish that content according to further instructions you give it, but it cannot work out the initial optimal architecture for your content. That is far too strategic a decision for a CMS to make.
• It does not create content; it only manages it. It will happily work with external content authoring tools and will create publications that are unique configurations of the content that it is managing, but a CMS alone does not originate content or design publications.
• It does not know what good content is. It does not even know the meaning of your content. It is, after all, just a dumb computer that will be quite happy to efficiently manage total nonsense.
• It does not process transactions. For that, you will still need a transactional system such as an e-commerce engine.
• On the whole, it is not that great at providing analytical information. It provides the necessary structure for a separate tool to do this job.
• It does not design for you.
• It does not know how to fix bad business processes.