> Software houses optimize for feature delivery and not user interaction time. Yet if I spent one hour making my app one second faster for my million users, I can save 277 user hour per year. But since user hours are an externality, such optimization never gets done.

Google and amazon are famous for optimizing this. Its not an externality to them though, even 10s of ms can equal an extra sale.

That said, i don't think its fair to add time up like that. Saving 1 second for 600 people is not the same as saving 10 minutes for 1 person. Time in small increments does not have the same value as time in large increments.

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esafak 6 hours ago | parent [-]

1. If you can price the cost of the externality, you can justify optimizing it.

2. Monopolies and situations with the principal/agent dilemma are less sensitive to such concerns.

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bawolff 5 hours ago | parent [-]

> 1. If you can price the cost of the externality, you can justify optimizing it.

An externality is usually a cost you don't pay (or pay only a negligible amount of). I don't see how pricing it helps justify optimizing it.

	▲	esafak 4 hours ago \| parent [-]
		You are right. I should say perceived externality; there may be a price that is discounted.