The Collison installation: more diffident founders ask "Will you try our beta?" and if the answer is yes, they say "Great, we'll send you a link." But the Collison brothers weren't going to wait. When anyone agreed to try Stripe they'd say "Right then, give me your laptop" and set them up on the spot.

Almost all startups are fragile initially. Inexperienced founders, investors, and reporters unconsciously judge larval startups by the standards of established ones — like looking at a newborn baby and concluding "there's no way this tiny creature could ever accomplish anything." The big danger isn't that others dismiss you; it's that you dismiss yourself.

The question to ask about an early-stage startup is not "is this company taking over the world?" but "how big could this company get if the founders did the right things?" The right things often seem both laborious and inconsequential at the time — like Brian Chesky and Joe Gebbia taking "professional" photos of their first hosts' apartments.

Insanely great in a larval startup doesn't mean the product — it means the experience of being your user. You can and should give users an insanely great experience with an early, incomplete, buggy product if you make up the difference with attentiveness. "I have never once seen a startup lured down a blind alley by trying too hard to make their initial users happy."

The contained-fire strategy: deliberately start in a narrow market to get critical mass. Facebook restricted itself to Harvard, then to specific colleges — Zuckerberg said creating course lists for each school made students feel the site was their natural home. Most startups that do this do it unconsciously by building for themselves and their friends.

Be your software before you build it. When you only have a small number of users, you can do by hand what you plan to automate later — Stripe's "instant" merchant accounts were the founders manually signing customers up for traditional merchant accounts behind the scenes. Less frightening than the far more common case of having something automatic that doesn't yet solve anyone's problems.

The Big Launch is a myth. Think of successful startups — how many of their launches do you remember? There may even be an inverse correlation between launch magnitude and success; the memorable launches are flops like the Segway and Google Wave. Founders fall for it from a combination of solipsism and laziness.

Stop thinking of startup ideas as scalars; think of them as vectors — pairs of (what you're going to build, the unscalable thing you'll do to get it going). An idea where the second component is empty — where there's nothing you can do to find initial users manually — is probably a bad idea.