When you're learning how to develop a race in any StarCraft 2 guide you should be able to discern the important role of cheese and be able to implement the information to develop a stronger race.
Cheese was a strategy that was introduced in StarCraft 1, and it basically just means that this is an "all-in" attempt. With a strong cheese attack, even the best strategist will struggle to regain their original strategy. In some cases it means that the game is over. A cheese attack in the earlier stages when few units are built to capacity will almost always mean that the end has come. In order to properly defend against a cheese attack you have to understand it and build proper defenses.
For those who embraced the cheese attack in StarCraft 1, they will be happy to find that its effectiveness and usefulness is still alive and well in StarCraft 2. A big part of its effectiveness is the element of surprise. A well timed attack will take into consideration the position of the opponent and the apparent strength that the opponent displays. For this reason, cheese attacks are almost exclusively used in the beginning of game play. Without a well established force built up and ready to defend, this is the sort of attack that can do some very significant damage.
Preparing for a cheese attack is also part of whether or not it becomes effective. In many cases, you really can't be conservative. You have to be willing to risk the economic stability as well as risk the development of other aspects to ensure that you can build up your forces quickly. The Terran bunk rush or the Protoss cannon rush are examples of well executed cheese attacks. By learning how to implement these types of attacks you should also be learning how to be prepared to defend against an attack like this from an opponent. A quality guide will be helpful.
The Zerg six pool strategy is basic and simple. If you deploy this strategy early enough in the game you could very easily win. Dumping every resource you have into building your forces at the very start of the game and top building a spawning pool which spawns 6 at a time. The Zerglings created will be available to immediately provide a cheese attack and either damage or wipe out your opponent.
You'll need to build a forge to implement the Protoss cannon rush. Build it immediately following your gateway. Follow this with pylons and the photon cannons to end the work of the opponent's mineral supply and take down any force resistance.
The terran bunker rush is based on building bunkers within the closest possible proximity to the mineral line of your opponent. Make sure you are also creating marines at the same time. The marines load into the bunkers and the opponent's mining will come to a direct halt.
As you play and read the StarCraft 2 guides, be sure you develop strategies to undermine an opponent's attempts to place a cheese attack on you. This way you will be able to defend against them as well as you employ them.