The first ten customers who are not doing you a favour

Early demand is easy to manufacture and hard to read. The discipline is separating people who want the problem solved from people who want to be supportive.

Whiteboard covered in notes and diagrams

Interest expressed in a conversation costs nothing, so it is produced generously. The useful question is not whether someone likes the idea; it is what they have already done about the problem before meeting you. Someone running a painful spreadsheet workaround every week has demonstrated demand. Someone who finds the idea interesting has demonstrated politeness.

Signals, ranked by how expensive they are to fake

Why the first segment should be narrower than comfortable

A narrow segment makes the product legible: the same objections recur, the same integrations matter, and word travels because the people know each other. A broad early segment produces an average of several products and a roadmap that satisfies nobody in particular.

A useful test: can you name twenty specific organisations in your first segment, with the person inside each who would own the decision? If not, the segment is a description rather than a market.