Many founders mistakenly define Product-Market Fit by revenue (e.g., "$1M ARR"). The correct measure is the ability to predictably create customer value. This is best quantified by a leading indicator for long-term retention, not sales figures, as revenue can be achieved without true market fit.

Rabois introduces a nuanced framework beyond just product-market fit. He argues that exceptional marketing can create a temporary illusion of success, but this "marketing fit" will eventually collapse if the underlying product value isn't there to retain users.

Intense early customer love from a small, specific niche can be a false signal for product-market fit. Founders must distinguish between true market pull and strong fit within an unscalable sub-market before they saturate their initial user base and growth stalls.

Product-market fit isn't just growth; it's an extreme market pull where customers buy your product despite its imperfections. The ultimate signal is when deals close quickly and repeatedly, with users happily ignoring missing features because the core value proposition is so urgent and compelling.

Legora's founder felt "fake product market fit" when a single presentation generated 150 demo requests. True PMF only arrived after rebuilding the product to be scalable and reliable, proving that intense initial interest doesn't equal a sustainable business.

Technical founders often create a perfect solution to a real problem but still fail. That's because problem-solution fit is useless without product-market fit. An elegant solution that isn't plugged into the market—with the right GTM, pricing, and messaging—solves nothing in practice. It's unheard and unseen.

PMF isn't a fixed state achieved once. It's a continuous process that must be re-evaluated at every stage of growth—from $1M to $1B. A company might have PMF for one scale but not for the next, requiring a constant evolution of strategy and product.

Having paying customers doesn't automatically mean you have strong product-market fit. The founder warns against this self-deception, describing their early traction as a "partial vacuum"—good enough to survive, but not to thrive. Being "ruthlessly honest" about this gap is critical for making necessary, company-defining pivots.

Success in startups requires nuanced thinking, not absolute rules. For instance, product-market fit isn't a simple 'yes' or 'no' checkbox; it exists on a spectrum. Learning to see these shades of gray in funding, marketing, and product strategy is a hallmark of a mature founder.