Why do (most) Wind Turbines have 3 blades?

Wind turbines provide a clean energy source, use little water, emitting no greenhouse gases and no waste products during operation. Wind turbine uses the renewable energy from wind to operate. Over 1,400 tonnes (1,500 short tons) of carbon dioxide per year can be eliminated by using a one-megawatt turbine instead of one megawatt of energy from a fossil fuel.

Wind turbines work on a simple principle: instead of using electricity to make wind like a fan, the wind turbines use wind to make electricity. Wind turns the propeller-like blades of a turbine around a rotor, which spins a generator, which creates electricity.

Have you ever wondered why most wind turbines have 3 blades, and not more or not less? There's a scientific reason for why 3 is the magic number.
This video will help you to understand why.

The links which helped to know more about this topic:

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[betespatiotemporelle]

Why this fear of high speed winds ? In the 1950s the French Compagnie industrielle des aéromoteurs (CIAMO) made a wind turbine made of flexible blades working even in a cyclone (90m/s). And I think they had 2 blades, as the protection came from flexibility.

[harry]

I read somewhere that the blades are affected as they pass in front of the tower..; Especially two bladed turbines.

[jerrydixon]

What I want to know is why is it when I see a field with 100 windmills, only 30 are moving?

[wadejenkins]

3 blades are physically unbalanced. The weight of 2 blades are on one side versus the weight of 1 blade countering. That weight difference changes sides 9 times with each revolution.
This sets up stresses in the tower that have to be modulated resulting in loss of efficiency and structural fatigue and failure.

[mf]

Aesthetics also... 3 blade turbines are better looking than 2 blade ones.