Choosing a dataset people will pay for

The best data products start with a list someone already builds by hand.

• Find the manual job. Who copies records from a public site into a spreadsheet every week? That is your customer.
• Check the source. Is it public, stable and allowed to be reused? Read the terms. Avoid anything personal or sensitive.
• Check the freshness. Daily or weekly updates make a subscription make sense. A once-a-year list is a one-time product.
• Check the action. The list should lead to a clear next step: a call, a letter, a visit, a bid.
• Start with one area. One region or one category is enough to learn what people actually use.

If you cannot describe the customer's Monday morning with your list in it, keep looking.