During my internship at TGR, one of the project's requirements was indexing and managing documents, and that was my first experience with Alfresco, which is an open source Enterprise Content Management (ECM), it combines a collection of content-centric technologies like Document Management (DM), Records Management (RM), and other technologies that should make your life, if your field of work is Content Management, easier.
Customizing Alfresco can be a bit tricky, and hard to grasp at first, but after doing it few times, you start to get the feel of it, and this post, as well as the future articles about Alfresco, are all here for you to get there.