Omer,
Alfresco is one of the most flexible and extensible ECM solutions out there, it has mostly all the features of FileNet and Documentum in addition to some extras. As we all know different systems use different terminology so it becomes confusing etc.
One of the reasons to have different document types in FileNet is to have custom properties (meta-data), in Alfresco you can accomplish this (custom properties) a couple of ways:
- Custom aspect: you can create a custom aspect and have your additional properties there. You can then attach this aspect to a space (folder) using business rules to capture this data when document gets uploaded in that space (meta-data)
- Custom content types: By default Alfresco comes with content type (base type) you can extend this to create you own type.
Both of these customizations can be accomplished by extending model.
Please let me know if this helps. Also, let me know if you need examples for the above