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  • Aaron Wolfson thinks this is interesting:

By building a few one-page sites, you can get a ballpark figure of the number of people who are interested in paying you to solve their problem. And the great thing is, you can start doing this before you start building anything. This means if nobody shows any interest in using your product, you can keep looking for new product approaches very cheaply until you find something that people are interested in using.

From

Cover of UX for Lean Startups

Note

Essentially, "why should this thing exist?"