In my first start-up, I had an initial advertising budget of $5 per day total. That would buy us 100 clicks per day. At $5 per day, marketing people scoffed and said that is too small to matter. But if you think about it, to an engineer, 100 real humans everyday giving your product a try means you can really start improving.

Learning is the essential unit of progress for startups.

Except in very narrow cases, where there's breakthrough science that needs patent production, worrying about competitors is a waste of time. If you can't out iterate someone who is trying to copy you, you're toast anyway.

Lean thinking defines value as providing benefit to the customer; anything else is waste.

The big question of our time is not Can it be built? but Should it be built? This places us in an unusual historical moment: our future prosperity depends on the quality of our collective imaginations.

If the plan is to see what happens, a team is guaranteed to succeed - at seeing what happens - but won't necessarily gain validated learning - If you cannot fail, you cannot learn.

Zero invites imagination, but small numbers invite questions about whether large numbers will ever materialize.