How we built Heroku CI: our product intuition checked against what the market wants (we surveyed ~1000 developers to figure out the latter, and the results were surprising)
Two approaches to building any product are often in tension: designing from inspiration, and designing from information. On the pure inspiration side, you just build the product you dream of, and trust that it will be so awesome and useful, that it will succeed in the market. On the pure information side, you build exactly what the market is asking for, as best you can tell (think: surveys, top customer feature requests, consultants, customer panels).
Our initial design for Heroku CI (currently in public beta) was...