The triangle is upside down:
If anything a regular pyramid makes more sense to me: you want the smallest/narrowest useful description at the top and then you gradually expand on it as you go down, providing more (wider) context and detail for the key information.
Edit: Of course, it's a widely used term and good to understand in that context; the Wikipedia link is useful.
This is often the case with geometric metaphors. They catch on easily, but they rarely make a lot of sense on closer scrutiny.