Use-value is not a quantity, but a collection of qualities. It is what makes any given commodity useful. For example, long battery life is part of an electronic device's use-value.
Exchange-value is how much one commodity is exchanged for another. At first glance, this may seem like some sort of arbitrary proportion, and an intrinsic exchange-value might seem like a contradiction in words, but both are untrue. Every commodity must have an infinite amount of exchange values, each corresponding to each-other. Ergo, there must be something within the commodity that is universal in all commodities, and allows every commodity to have an exchange value that is not a proportion, but a quantity.
The only universal property in all commodities is that they are made of labor. Labor is quantified with hours, days, and weeks. Ergo, exchange-value is an intrinsic quantity corresponding to how much labor is put into a commodity. You may think that the things made by an inneficient laborer would, therefore, be more expensive. They wouldn't, because commodities are priced as a whole, one gala apple from the same company wouldn't cost more or less than another. This means that the universal labor put into all gala apples from that companies is what sets the price. In other words, the exchange value is the average time under average conditions for an average worker to create one commodity.
When corporations revolutionize technology, temporarilly they can produce a commodity more efficiently than anyone else. Than, other corporations adopt what the first corporation used, and the value of the commodity goes down. Because of this, corporations have to constantly revolutionize technology again and again in order to produce more and create more of a commodity.
Corporations producing so much translates to an excess of product, that corporations must halt production to sell. This causes a large-scale crisis, as millions of people are out of a job, and cannot afford to buy the product from a corporation. Therefore, corporations go out of business, and employees starve.
These crises get worse over time. As technology gets better, the excess gets larger and larger, creating bigger and bigger crises.
There is one alternative. Capitalism in extreme decay -- fascism. Fascism is a method to regulate workers with a police state protecting the bourgeoisie and putting a stop to revolutionary proletarian movemements. When the bourgeoisie can no longer do with pretending to be democratic, they become fascistic. As the Georgi Dimitrov, the Marxist-Leninist-Stalinist who was released from Nazi Germany because he exposed them so thoroughly, said, "The accession to power of fascism is not an ordinary succession of one bourgeois government by another, but a substitution of one state form of class domination of the bourgeoisie -- bourgeois democracy -- by another form -- open terrorist dictatorship."
Ussually, fascism is implemented when there is about to be a proletarian revolution in the country, so they implement a terroristic jingoistic dictatorship. For example, in Russia just before the Russian Revolution, fascism began to put its roots on the ground, after a demonstration for bread and peace was massacred. This was enabled by social democrats such as the Mensheviks and the Socialist-Revolutionaries (who weren't really all that revolutionary). However, the Bolshevik revolution happened, which stopped fascism from taking Russia as its host nation.
Socialism can prevent crises, fascism and the decay of society. Under socialism, production is social, and products are produced not for profit but in order to be used. This means that enterprises and factories under socialism have no readson to halt production, so they can produce more than can be sold, which means they can achieve true abundance and overcome the artificial scarcity created by capitalism and the crises it creates.
This is within the class interest of the proletariat, who would be fisically enriched if they would be able to get the surplus value that the bourgeoisie appropriates from them. This is against the class interest of the bourgeoisie, who would be fisically enriched by staying in power. Because of this, the proletariat is the only class that can advance society. The proletariat is the only possible revolutionary class.
Capital has a tendency to monopolize. When some companies cannot afford to produce as much as the ludicrous amount others are, they go out of business. There is also finance capital, which is the blurring of the line between bank and industrial capital. This means that banks are providing factories with money-capital (capital in money-form), and factories are paying back their loans, making both parties a profit. Finance capital has the added effect of adding pressure on companies, as if they don't pay back their loans they will go bankrupt.
When a company has a monopoly (or oligopoly) over one area of the world and still needs to grow, it resorts to exporting its capital (instead of commmodities) elsewhere and earns more money there. This is the beginning of imperialism. The resulting profits are known as superprofits.
But what if you lose your money? What if the government there starts not letting you export your capital? The best option to get rid of these concerns is installing your own government there. You can do this either by invasion or by installing a government of the comprador bourgeoisie of a nation -- people from that nation, but that profit from you imperialising their nation.
In this manner, the bourgeoisie of different nations imperialises different nations. But empires are constantly fighting over the distribution of every area. Because of this, most wars occur. Some wars are not inter-imperialist wars, such as civil wars in which one class fights against another, or national-liberation wars in which an imperialized power fights against an imperialist one.
Some workers benifit from this. These are called the labor aristocracy -- those workers which capitalists give the crumbs of their superprofits in order to make them more loyal to capital.
For the proletariat to succeed, it needs to organize the most class conscious, advanced members of the masses, known as the vanguard into a party known as the vanguard party. This vanguard party will lead other workers' organizations such as workers' councils, labor unions, etc.
The workers will also need to repress the bourgeoisie's attempts to regain power, and exercise their authority while doing so, which some bourgeois theorists call "authoritarianism."
Socialists cannot become social-chauvinists once an inter-imperialist war begins. They must wish for the defeat of their government and of the other side's government, and for the success of the international proletariat. This is an example of proletarian internationalism.
Because different countries are at different stages in the development of capitalism, and a proletarian revolution needs certain development of capitalism to occur, simultaneous international revolution is impossible, but this does not mean not to fight for the international proletariat, and by no means does it mean that the proletarians of all countries cannot unite.
Anarchism is fundamentally wrong in that it does not allow for the workers' to use a state, a weapon of one class against another, to repress the bourgeoisie and prevent their return to power, as has happened so many times in anarchist experiments, many of which barely lasted more than a month.