Over the years document management software vendors have tried to produce a platform to meet the requirements of the entire enterprise, in all document management categories. An early philosophy was to centralize every piece of content into one repository. More conventional thinking is to have different systems to more comprehensively meet the requirements of the enterprise while unifying the user experience via portal technology.
 
The different document management categories:

• Core Document Management – This can be considered an extension to the corporate file-share, organizing documents with a defined taxonomy (attributes, security, foldering, categorization etc). Library management controls the version control of documents, with audit trails and security providing a foundation for compliance
• Web Content – This category focuses around web content authoring and delivery, and allows sites to be organized into static and dynamic content delivery with real-time site updates
• Imaging Management (Transactional) – This category can sometimes be called transactional document management (documents resulting from a business transaction, such as invoices, POs, Bill of Laden, Patient Records, Loan Documents etc). These systems are designed to manage a high-volume of fixed content and as the documents can be large these system can have technology to deliver small sections of the documents to client at a time to increase performance. Report management can often be in this category, which is sometime called COLD and is a technology that ingests, separates and extracts data from reports produced from business applications
• Collaboration – Can be considered an extension of the Core Document Management category and includes content into different collaboration methods, such as blogs, wikis, discussion groups, and web content based presentation to allow team of users to interact and work with the content
• Capturing Content – All the above system categories need a way of getting content or documents into them, and this category is often overlooked but can be considered one of the most important aspects. The more content that is under the control of the system, the more value it has

When selecting a system, you have to compare your requirements against the different categories as you may not need all components. Also, if you do select different components from different vendors, make sure you have a way of unifying user access.