Most startups are not just built for the person who is using them. When you do that, every now and then you get really lucky and... are representative of some huge class of people who all want the same thing you do... but very often that just turns into a side project that doesn't go anywhere.

Users think they know what they want, but you get the horseless carriage effect where you're getting asked for a faster horse.

Sales is this cure all for this problem. Get people to give you their credit card and I guarantee you they're actually interested.

The pool of people you care about is going to shift over time.

The Twitch community loves watching video games, chatting, and broadcasting. The average viewer watches over an hour and a half of video each day. Over two-thirds of our logged-in users chat each day.

The crucial people to get your product started for the first 6 months are not who will be using it 3 years later.

If you just talk to who's easy to talk to, you're not really getting the best data.