“I don’t see the appeal in using most social networks. They require lots of input: who are you? what do you do? where do you work? what do you like? who are your friends? In return for all this input, you get very little.

“I perceive Emacs as a huge ship where people embark to travel around the planet. However the ship is heavy and consumes a great deal of fuel to effect only slight changes in direction. It is difficult to find captains for this ship. Its voyages do not fully track the mainstream routes, where the active and diverse crowd is. This is because captains are not that concerned with the mainstream, and also because when corrections become unavoidable, its inertia is such that it always lags a bit from the aimed route. So this ship very slowly diverges, progressively isolating its happy passengers from the rest of the world.

“In Galileo’s time people assumed that the Milky Way must be some kind of continuous substance. It truly resembled a streak of spilled liquid—our word “galaxy” comes from the Greek for milk—and it was so bright that it cast shadows on the ground (as did Jupiter and Venus).

Today, by contrast, most Americans are unable to see the Milky Way. Those who can are baffled by its name. The stars have not become dimmer; rather, the Earth has become vastly brighter. Air pollution has made the atmosphere less transparent and more reflective, and washed out the stars overhead.

“We—you, me, anyone who programs because they love it, who would do it for free if necessary—are a breed apart. It isn’t intelligence, or hard work, or education, although those help; it’s that we actually like this stuff.

I’ve seen far too many people start to treat programming like a job, forgetting the joy of doing it, and burn out. So keep an eye on how you feel about the programming you’re doing, and if it’s getting stale, it’s time to learn something new; there’s plenty of interesting programming of all sorts to be done. Follow your interests—and don’t forget to have fun!

“You had to put the alphabet into an order, because otherwise you couldn’t remember what all the letters were. The order they picked is as good as any other. They just picked it.

“When I give a draft of an essay to friends, there are two things I want to know: which parts bore them, and which seem unconvincing. The boring bits can usually be fixed by cutting. But I don’t try to fix the unconvincing bits by arguing more cleverly. I need to talk the matter over.

“Creating an infrastructure for managing the content you wish you had doesn’t actually create that content.

“Seeing is forgetting the name of the thing one sees.

“Meeting the market’s demands is how application code becomes beautiful in a commercial sense.

“The hardest part about writing a search engine is that you’re going to process billions of URLS and serve millions, if not billions, of queries. This does not leave a lot of room for error. One super-linear algorithm applied over the wrong-sized list of items and you are sunk. One lock inside another lock and you are sunk. There will be no code paths not explored. All of those comments in your code, which print out errors like “This will never happen,” will happen.