This is a debate that will never be settled. Plenty has been written about how to define product/market fit. The consensus seems to be: (a) it’s generally easier to identify when you don’t have it, and (b) when you do, it’s hard to objectively point to why. It’s just a hunch. A feeling.
Marc Andreessen’s article from 2007, “The only thing that matters”, is probably the standard-bearer. He writes:
Product/market fit means being in a good market with a product that can satisfy that market.
You can always feel when product/market fit isn’t happening. The customers aren’t quite getting value out of the product, word of mouth isn’t spreading, usage isn’t growing that fast, press reviews are kind of “blah”, the sales cycle takes too long, and lots of deals never close.
And you can always feel product/market fit when it’s happening. The customers are buying the product just as fast as you can make it — or usage is growing just as fast as you can add more servers. Money from customers is piling up in your company checking account…
That’s as good as any I suppose.
But, let me point to another way of thinking about it, which comes from my good friend Nicolas Colin of The Family. Nicolas helps people identify when product/market fit is or isn’t happening in a rather unique way, by drawing on a historical narrative from politics.