Everything you can do with a folder, you can do with a Keep-It archive. Everything you can do with a file, you can do with a revision. Here's a complete description of the facilities Keep-It provides. If you don't know what Keep-It does, maybe viewing the demonstration could provide an introduction. I'll try and give a brief overview here, but it's easier to see and use than explain.
Archives behave just like folders.
Archives contain revisions of the items you put in them. They put these in what we call snapshots . You now know all the terminology. Let me explain this further. Revisions are grouped in time-stamped containers called snapshots.