Move 37 from AlphaGo is very interesting. I was watching the game live and was stunned to see it. It is the kind of move you might see from people who have just barely learned the rules of the game and learned about a "shoulder hit" and tried to implement it improperly. These beginners would naturally be told "do not shoulder hit on the 5th line". A little bit about these terms:

Lines in Go are counted from the edge of the board. Here's a visual of the 3rd line for example: https://senseis.xmp.net/?ThirdLine

The 1st line is uninteresting. The point of Go is to surround territory. You cannot surround any territory on the 1st line. Players try to avoid playing on the first line until the end game.

The 2nd line is called the "line of defeat". It really only "catches" 1 point of territory (the point on the first line). If players take turns playing on the 2nd and 3rd lines next to each other, with the 2nd line player taking 1 point of territory, and the 3rd line player taking no territory but outward influence, it is considered a great victory for the 3rd line player because center influence is generally counted as worth 2 points per stone of influence. This is a loose count, because it's not actually any real points, but generally accepted as reasonable. Here's a visual: https://senseis.xmp.net/?TheSecondLineIsTheRouteToDefeat

Side note: "Influence" is the term used to describe how stones facing toward the center affect the flow of the game. They don't give direct points, but a skilled player can use their influence throughout the game to control the direction of the game and thus gain points in the future.

The 3rd line is the "line of territory". Each stone here gets about 2 points of territory. Players are usually happy to be able to make moves along the 3rd line, especially if they can do so while doing something else, or while maintaining control of play.

The 4th line is the "line of influence". Similarly to the 3rd line, players are often happy to be able to play moves along the 4th line because stones on the 4th line will be advantageous throughout the game. While plays on the 3rd line often don't give influence (because their influence is easily countered by 4th line plays by the opponent), players are happy with the territory they provide. Similarly plays on the 4th line don't give territory (the territory can somewhat easily be scooped up by plays along the 3rd and 2nd line), but players are usually happy with the influence the 4th line provides.

Thus the 3rd and 4th lines are the most common lines for play. 3rd line for when a player wants territory, 4th line for when a player wants influence.

The 5th line is very much approaching the center of the board. https://senseis.xmp.net/?FifthLine . While it gives similarish influence to the 4th line, it is even easier to scoop out territory from under it. Usually players avoid playing on the 5th line unless there's a specific reason such as strengthening a position or pressuring an opponent. It's not an unplayable move to play on the 5th line in general, and some players experimented with playing more on the 5th line, but it's not considered as valuable as the 3rd and 4th lines.

A shoulder hit is a tactical move where a player pushes their opponent from behind. Usually it turns into a move where both players end up trading moves along 2 different lines. https://senseis.xmp.net/?ShoulderHit

As such, shoulder hits have historically been very common on the 4th line. This happens when a player has a stone on the 3rd line and their opponent plays an attack move on the 4th line diagonal to it. Often both players will take turns from there strengthening their position along the 3rd and 4th lines. The 3rd line player takes territory and the 4th line player takes influence. This is often considered a fair trade.

But AlphaGo played a shoulder hit on the 5th line. This looks like a rookie mistake because that forces the opponent to take territory on the 4th line. If both players take turns building from there, the 5th line player gets "2 points" of influence while the 4th line player gets "3 points" of territory.. for every stone played on these lines! This is the kind of move that is commonly told to beginners "do not shoulder hit on the 5th line". It is a mistake. Most people just learn not to consider it.

I hope this helps :)