Socialism is an economy in which productive property (factories, farms, workshops) is controlled socially. This can mean direct workers' control, or community ownership, or state control on behalf of the people. There are a great deal of socialist ideologies. Broad categories include democratic socialism, Marxism, and anarchism.

Communism is a classless, stateless society in which productive property is commonly owned and economic distribution is operated on the principle of "from each according to his ability, to each according to his need." It also refers to a group of ideologies which hold this form of social organization as their end goal. The most significant form of communism is Marxism, and the 20th century was characterized by a number of Marxist-Leninist states. Anarchist communism is also historically significant, though has not been nearly as popular as the various forms of Marxist communism since the late-19th and early-20th centuries, except in select countries or localities.

MARXIST SOCIALISM/COMMUNISM

Marxism is an analytical framework based on the writings of 19th century German philosopher, economist, and sociologist Karl Marx and political philosopher and social scientist Friedrich Engels. It holds that human society is built primarily on economic relations between classes and that political and social structures are built around these relations. One's class is defined by one's relationship to production—who owns capital, who works it for a wage? Marxism analyzes social changes and developments as the product of conflicting classes changing the structure of the economy. Modern capitalism as the result of the bourgeoisie, the current capital-owning class, having wrested control of the economy away from the aristocracy, or the feudal owning-class. Bourgeois democracy follows as political structures adapt. The primary class conflict in capitalism is between the capital-owning class (the bourgeoisie) and the working-class (the proletariat). Marx argued that the proletariat would seize control of the economy and society, in a stage he described as socialism. In Marxist analysis, every state is the "dictatorship" of the economically dominant class. The socialist stage is therefore the "dictatorship of the proletariat," in which the workers will reorganize the economy until there are no longer any classes. Without a class that needs to enforce its dominance over others, Marxists believe that the state will wither away and the final stage, communism, will be reached. These socialist revolutions will happen when capitalism reaches its final stages of development and becomes consumed by its own contradictions. There's a great deal of in-depth theory here—this is just the barest summary.

Marxism-Leninism is a term coined by Joseph Stalin to describe the ideology of the Soviet Union during his time, though Leninism also refers more broadly to the ideas of Vladimir Lenin. The bolshevik faction of the Russian Revolution, lead by Vladimir Lenin, established the Soviet Union and had huge influence on the global left. Lenin made theoretical additions and alterations to Marxism. For instance, Marx argued that truly successful socialist revolutions could only occur in fully industrialized economies in the high stages of capitalism. Lenin, however, claimed that revolution would occur where capitalism was weak, like in semi-feudal Russia which was in earlier stages of capitalism than Germany or Britain. Marx's conception of the dictatorship of the proletariat was purposefully vague, though in his life he did point to the Paris Commune as an example. Leninism introduces the vanguard party, which is an organization of a particularly class conscious sector of the working-class (though some bolshevik leaders like Lenin, Trotsky, and Stalin were not working-class) which seizes control of the state and guides the rest of the working-class to socialism. After Lenin's death, Stalin's codified Marxism-Leninism also included the idea of Socialism in One Country: that a Marxist revolution didn't necessarily have to engulf all the world at once and that Marxist-Leninist states should focus on strengthening themselves and building socialism internally.

Trotskyism is a Marxist and Leninist (but not exactly "Marxist-Leninist") ideology based on the theories of Russian revolutionary Leon Trotsky. The leader of the Red Army during the revolution and civil war, Trotsky was an opponent of Stalin during a 1920s power struggle and therefore Trotskyism doesn't grow out of the exact ideology of "Marxism-Leninism" coined by Stalin so much as from the Leninism of the revolutionary and early Soviet years. It has similar ideas of a vanguard party, though criticized the Soviet Union as a degenerated workers' state in which the state was no longer worker-controlled but instead controlled by Stalin's bureaucracy. Trotsky also had the theory of permanent revolution, in which a workers' revolution in an economy which had not yet experienced a complete bourgeois capitalist revolution could carry out the necessary developments of the bourgeois revolution and its own revolution. This revolution could not survive long under assault from outside capitalists, and so Trotsky argued that it must be constantly expansive, rather than focused on building socialism in one country. Expanding the revolution to Germany, for example, would not only put class enemies on the run but also allow Germany's more advanced industrial base—the product of a more complete bourgeois revolution—to speed Russia's journey to socialism. Personally, Trotsky saw himself as a Leninist.

Maoism is a development of Marxism-Leninism based on the work of Chinese revolutionary Mao Zedong, and is sometimes called Marxism-Leninism-Maoism. It is "anti-revisionist," meaning that it is based in Stalin's conception of Marxism-Leninism and critiques the post-Stalin reforms of Nikita Khrushchev and other Soviet leaders as abandoning the revolution. Maoism draws lessons from the Chinese revolutionary experience and a theoretical base from Mao's additions to and adaptations of Marxism-Leninism. It focuses more on the peasantry—which Mao saw as proletarianizing—as a revolutionary class and puts more of an emphasis on agrarian communities as the center of socialism and the site of future industrialization. In comparison, classical Marxism was more focused on urban, industrial centers. Third World countries, the victims of imperialism, are the places where Maoist revolutions will begin because capitalism has not made the kind of appeasement to workers there as it has in wealthier countries. Maoism also adds ideas like the Mass Line to the vanguard party, in order to constantly incorporate the ideas of the masses into party policy. Mao argued that bourgeois ideology does not go away after the revolution, and must be defeated through cultural revolution, a struggle that continues under socialism.

NON-MARXIST SOCIALISM/COMMUNISM

Democratic socialism broadly describes any socialist economy which is accompanied by a democratic political system—and thus can include forms of Marxism and anarchism. The term is also used more specifically to refer to socialism either achieved through the liberal democratic state—a tactic sometimes called "social democracy" depending on which definition of that term you're using—or with a political system somewhat based on modern liberal democracy. This more specific definition would be critiqued by Marxists for trying to change an economic system through the structures built to sustain that system. However, democratic socialists and Marxists have sometimes made common cause. Democratic socialists vary widely without a major unifying ideological figure or body of work, and can represent state control of the economy or a small government overseeing community, market, or collectivist forms of socialism.

Anarchism is a broad collection of stateless socialist systems. While the word "anarchy" is used colloquially to mean chaos or lawlessness, anarchists maintain that non-hierarchical social equality creates a more ordered society. Anarchism, as a socialist ideology, critiques capitalism. The most historically significant forms—anarchist communism and anarcho-syndicalism, which are compatible—do so in a way similar to Marxism. However, anarchist communists believe that the state, which concentrates power, cannot be used to abolish class society and will not wither away on its own. Syndicalist revolutions, as in 1936 Spain, attempt to directly seize and reorganize the economy through democratically run industrial labor unions, rather than through the state. An anarchist society is typically governed through community democracy and temporary delegate systems, rather than through fixed representatives in a permanent state structure. Market forms of anarchism—like mutualism—exist, but anarchist communism would be a decentralized planned economy based on principles of mutual aid and organized globally between communities and industry-wide workers' syndicates. There's much more to say here, but anarchism doesn't seem very relevant to what you're studying, so I'll leave off it.

---

---

why are they so popular in developing nations?

Well, I can't say for sure, but if you look at what socialism promises—workers' control, economic equality, prosperity—then it's hardly surprising that it would take off in areas with high rates of poverty and economic insecurity among the working classes. Realities and results have of course varied widely depending on the characteristics of individual movements.

I can't speak much to Sri Lanka, but I anticipate you'll be looking into Marxist-Leninist groups. I'm not an expert in every topic I've covered here, but let me know if you have any more questions.