Socialism is a political philosophy with the core belief that "the people" should control the means of power, including the means of production with the goal of building a classless society. In practical terms it means havign a big state and having the public sector provide most of the basic needs of individuals and communities. Socialism has a long history of revolutionary attitudes, but modern socialism has increasingly, become concentrated on reforms within the system of modern democracies. This concept and the term socialist also refers to an economic system, of central economic planning that exists or has existed in Soviet or other Communist countries. Marxism and communism are both very specific branches of socialism that do not represent socialism as a whole.

\Historically, the ideology of socialism grew up hand in hand with the rise of labor unions. In many parts of the world, the two are still strongly associated with one another; in other parts, they have become two very distinct movements.

Branches of socialism
http://en.wikipedia.org/wiki/Socialism#Branches_of_socialism - see wikipedia.

Sources and Resources:

Socialism - Wikipedia