According to Julie

From In the Beginning... Was the Command Line by Neil Stephenson:

Imagine a crossroads where four competing auto dealerships are situated. One of them (Microsoft) is much, much bigger than the others. It started out years ago selling three-speed bicycles (MS-DOS); these were not perfect, but they worked, and when they broke you could easily fix them.

There was a competing bicycle dealership next door (Apple) that one day began selling motorized vehicles—expensive but attractively styled cars with their innards hermetically sealed, so that how they worked was something of a mystery. The big dealership responded by rushing a moped upgrade kit (the original Windows) onto the market. This was a Rube Goldberg contraption that, when bolted onto a three-speed bicycle, enabled it to keep up, just barely, with Apple-cars. The users had to wear goggles and were always picking bugs out of their teeth while Apple owners sped along in hermetically sealed comfort, sneering out the windows. But the Micro-mopeds were cheap, and easy to fix compared with the Apple-cars, and their market share waxed.

Eventually the big dealership came out with a full-fledged car: a colossal station wagon (Windows 95). It had all the aesthetic appeal of a Soviet worker housing block, it leaked oil and blew gaskets, and it was an enormous success. A little later, they also came out with a hulking off-road vehicle intended for industrial users (Windows NT) which was no more beautiful than the station wagon, and only a little more reliable.

Since then there has been a lot of noise and shouting, but little has changed. The smaller dealership continues to sell sleek Euro-styled sedans and to spend a lot of money on advertising campaigns. They have had GOING OUT OF BUSINESS! signs taped up in their windows for so long that they have gotten all yellow and curly. The big one keeps making bigger and bigger station wagons and ORVs.

On the other side of the road are two competitors that have come along more recently.

One of them (Be, Inc.) is selling fully operational Batmobiles (the BeOS). They are more beautiful and stylish even than the Euro-sedans, better designed, more technologically advanced, and at least as reliable as anything else on the market--and yet cheaper than the others.

With one exception, that is: Linux, which is right next door, and which is not a business at all. It's a bunch of Rvs, yurts, tepees, and geodesic domes set up in a field and organized by consensus. The people who live there are making tanks. These are not old-fashioned, cast-iron Soviet tanks; these are more like the M1 tanks of the U.S. Army, made of space-age materials and jammed with sophisticated technology from one end to the other. But they are better than Army tanks. They've been modified in such a way that they never, ever break down, are light and maneuverable enough to use on ordinary streets, and use no more fuel than a subcompact car. These tanks are being cranked out, on the spot, at a terrific pace, and a vast number of them are lined up along the edge of the road with keys in the ignition. Anyone who wants can simply climb into one and drive it away for free.

Customers come to this crossroads in throngs, day and night. Ninety percent of them go straight to the biggest dealership and buy station wagons or off-road vehicles. They do not even look at the other dealerships. Of the remaining ten percent, most go and buy a sleek Euro-sedan, pausing only to turn up their noses at the philistines going to buy the station wagons and ORVs. If they even notice the people on the opposite side of the road, selling the cheaper, technically superior vehicles, these customers deride them cranks and half-wits. The Batmobile outlet sells a few vehicles to the occasional car nut who wants a second vehicle to go with his station wagon, but seems to accept, at least for now, that it's a fringe player.

The group giving away the free tanks only stays alive because it is staffed by volunteers, who are lined up at the edge of the street with bullhorns, trying to draw customers' attention to this incredible situation. A typical conversation goes something like this:

Hacker with bullhorn: "Save your money! Accept one of our free tanks! It is invulnerable, and can drive across rocks and swamps at ninety miles an hour while getting a hundred miles to the gallon!"

Prospective station wagon buyer: "I know what you say is true...but...er...I don't know how to maintain a tank!"

Bullhorn: "You don't know how to maintain a station wagon either!"

Buyer: "But this dealership has mechanics on staff. If something goes wrong with my station wagon, I can take a day off work, bring it here, and pay them to work on it while I sit in the waiting room for hours, listening to elevator music."

Bullhorn: "But if you accept one of our free tanks we will send volunteers to your house to fix it for free while you sleep!"

Buyer: "Stay away from my house, you freak!"

Bullhorn: "But..."

Buyer: "Can't you see that everyone is buying station wagons?"

And now, with monkeys, added by Garrett Birkel:

(...) if you buy an Apple sedan, you also receive a little monkey in a snappy blue suit. Your personal X-Monkey (as the company calls him) is the ideal driver of your Apple sedan. He knows where everything is, feeds and washes himself, drives defensively, and will even tune up the car for you. X-Monkey will accept precise instructions like, "forward 10 feet, right 20 degrees", but he is smart enough to think on his own, so you can tell him "Drive me to a taco stand, then pick up Uncle Steve". He will also keep you out of trouble, by politely ignoring instructions like, "Run over that jogger", and "Floor it", when you're at a red light. Depending on your temperament, this could actually be a downside.

The X-Monkey comes from a line of monkeys originally bred by the military for the purpose of driving tanks. It's a good fit, because the modern Apple sedan is actually a tank in a fancy shell. The X-Monkey's only drawback is that he can only drive a car from Apple. Show him any other vehicle, and he won't even know how to operate the door lock.

Meanwhile, the free-thinking Linux people, displeased with genetic engineering, have created their own smart monkey chauffeurs through a massive international breeding program. Unlike the X-Monkey, the Linux Monkey is capable of driving any car, including the Apple sedan. If you could install a steering wheel on a log splitter, the Linux Monkey could drive it for you. The catch is, you have to train the Linux Monkey yourself. Fortunately there are experts everywhere who will help you out, and the Linux Monkey trains easily.

The Microsoft Gorilla, on the other hand, cannot be trained. Instead, you must keep rephrasing your directions until the MS Gorilla can comprehend them. He consumes both front seats, lowering the mileage of your car, and blocking most of your view. Though he sounds like a bad deal, MS Gorilla is actually extremely popular, because he looks impressive, drives aggressively, and keeps his mouth shut. If you speak in his limited vocabulary, he will take you Where You Want To Go Today ... especially if he can plow monkeys off the intervening road. However, if you touch anything on the dashboard, or try to haggle with him over the exact route, he may become irritated and casually drive your car into a telephone pole. People learn to not argue.

The point to this altered metaphor is that the Microsoft dealership, and the Linux collective, do not really make cars at all. All those shiny automobiles sitting on the lot and lined up on the street corner are re-branded vehicles, manufactured by other companies. However, their modern instrument panels are so confusing that they'd be useless without a chauffeur. ... And the Microsoft dealership gets a cut from the price of every vehicle that leaves their lot, piloted by the Microsoft Gorilla.

If you were so inclined, you could purchase a car from them, drive to the sidewalk, and kick the gorilla out onto the curb. The Linux Monkey can hop right in and start driving for you. Of course, Microsoft already has your money, and what are you going to do with a spare gorilla?

Contrast this with the Apple dealership, that personally designs and assembles every Apple sedan. When a sedan leaves their lot, they pocket the whole amount. You could still kick out the X-Monkey any time, but why would you? The Linux Monkey is basically the same, without the training.