The Johnny.Decimal system helps to manage information across multiple systems. It use a central index to reduce the question of, “Where do I store this?” to one of clearly identified locations.
More information can be found at the johnnydecimal.com.
In The ABCs of personal knowledge management I talk about the Getting Things Done methodology filing system which uses letters as filing. Is Origin Energy under ‘O’ for the company, or ‘E’ for electricity. It doesn’t matter, but is simple to find if used consistently. Johnny.Decimal adds another layer which I’m finding impinges quick filing without necessarily adding anything.