Partnerships and Shipping

I've been thinking a lot about partnerships lately.  I'm also reading Seth Godin's latest book, "Linchpin." (Not an affiliate link.)  A few moments ago, both trains of thought collided.  A single question emerged:

"What is this partnership going to ship?"

You can substitute 'produce' or 'create' for 'ship,' if that helps.  In other words,

"What are we going to ship/produce/create together (as partners) that we can't (or shouldn't) do separately?"

If we can't answer that question, maybe we don't know each other well enough to be partners.  We can like each other.  We can be friends.  We can even help one another on occasion.

But, if we can't answer the shipping question, I'm not sure we're ready to be partners.