terms such as socialism, liberalism, conservativism, rightwing, leftwing can have different meanings depending on the context of the discussion. so economic liberalism is different from politiical liberalism, which is different from moral liberalisim, which is different from religious liberalisim, which in turn may vary within differing religions.
Someone in the first couple of posts mentioned Keynsian and Friedman, when talking about economics this is a good place to start but i will try and simplify. Most of modern economics can be viewed from how you feel about market control vs market freedom.
so the first question to ask is do you understand what the market is? If you dont ask google, but you wont understand much of ecomonics until you do. You can view the market from two extremes. On one end, there are those who believe that the most efficient, productive and ultimatly fair system is to have a free unregulated market. This would mean that companies can trade with no restrictions, little to no tax, but under fierce competition from each other, the idea being that competition would drive them to offer a good deal to their customers and employees, and would provide motivation to deliver the best service, thus giving higher efficiency and fairness and affluence for all.
The other view is that the market will fail by its self. Either by over exploitation of the workers (Maxist theory), or buy over saving by companies or consumers, or lack of competition and the creation of monopolies, localised declines due to outsourcing (the list could go on), and you get situations like recessions where the economy crashes due to an inbalance or a failure in a vital sector. The solution to this is to regulate the economy with taxes, laws, tariffs, or even state ownership etc.
you should view
state controlled economy<------------------------->free market economy
as an axis, as most modern states are somewhere along the axis rather than at either end. North Korea is possibly the most state controlled. Not sure what the most freemarket is, possibly the US, but the US still uses tariffs to protect its steel industry, and has corperate taxes etc.
so what are capitalism, marxism and communism.
Capitalism is basically the idea that labourers should be able to sell their labour for personal material gain, or traders should be able to sell their goods for personal material gain. WIth out restrictions, and within a interlinked national or global system you get the market.
Karl Marx was an economic/political theorist.
http://en.wikipedia.org/wiki/Karl_marx. He release a manifesto (ive read it, arbeit along time ago). Which essentially says revolution against the rich is inevitable in a capitalist system. This will happen because the rich will reduce the working conditions of their labour / increase their own profits in order to improve their wealth. As the rich poor gap grows the rich will struggle to maintain control, and eventually - revolution of the poorer classes. Karl Marx then proposes that given time capitalist systems would colapse and the logical progression was to allow the workers to control production
Communisim is an extension of the idea that the workers, or for most communists the state, should control production. THis brings communism up on the extreme left of the axis i put above.
so which works,
well as someone has already stated neither. But no system will work perfectly because humans (and humanists can disagree with me here but the average front page of the news stands in my defence) generally seek to cheat and exploit each other for personal gain.
to say because they dont work perfectly they are all failures isnt really fair, and doesnt really encourage thinking.