Fuzzy on God? Part Deux?

I got into some conversations with several people since the original post; some were associated with the blog and the others were simply about the Trinity. A few observations on those conversations...

• 99.9% of the people I talked with admitted that the only Christian doctrine of God was and is trinitarian. No: none of them used the phrase "Christian doctrine of God," but they (you?) all had that intent!
• But the same 99.9% also admitted some degree of confusion as to: why the Christian doctrine of God had to be trinitarian, or why the doctrine always seemed so impenetrable, or why the doctrine seemed irrelevant to discipleship (and I'd hazard a guess: irrelevant to worship and mission).

It's not as though many of us have had someone assist us in understanding who God is from a trinitarian description. I know I did not catch this from the various churches I belonged to or served at; nor was I specifically sat down in seminary or in my ordination exams and asked to explain what I meant by "the triune God."

I do know that if you look at the IVCF Doctrinal Basis, you'll observe that it begins with a trinitarian depiction of God. In a conversation with a colleague last year, he informed me that he had initiated a reading group of young IVCF staff to discuss and learn together what it means to have faith in the triune God. While all of these staff had to sign a commitment to the above statement of faith, few had more than a slender understanding of what the doctrine meant and its implications for life and ministry.

These conversations reminded me of the Preface to Ted Peters' book on the Trinity, and I paraphrase here: "the Christian doctrine of God is the best-kept secret in the world."

What do you think are the implications for a lean understanding of the Trinity? Is this doctrine one that is so "academic" as to be useless for our season of humanity? Or is it a doctrine long overlooked but awaits some concentrated examination for our relationship with God, each other, and the world: and therefore become useful? And what would you mean for the word, "useful'?