Left communists are sometimes referred to as a variety of movements that criticize Bolshevism from the left. That is, being supporters of communism themselves, they blame the Bolsheviks for that they were either not consistent supporters of communism or even opponents of true communism.
The term "left communism" embraces all sorts of currents of left Marxist thought, first of all, the German-Dutch council communists and Bordigists (Italian left communists). In fact, these movements are very different.
Council Communists (Germany)
German council communists were in fact the most radical revolutionary force in Germany and, perhaps, in all modern European history. Their associations during the German Revolution (1918-1923) totaled up to 300 thousand people in the aggregate. Their ideas were close to anarchism, but more radical: they unequivocally rejected the unions and strongly supported worker’s self-organization in the form of councils. At the same time, there were some authoritarian currents among them. However, it is, in general, an anti-Leninist radical communism current, close to anarchism. It unites the advocates of self-government, councils, direct workers' democracy, opponents of the market, property and state. I should add that most of the historical council communists did not deny the organization and the role it plays. The organization, however, was understood as the inspirer of social revolution or the association of all social-revolutionary workers rather than the force destined to govern by command methods, like the Bolshevik Party. Otto Rühle, one of the council communists’ leaders once said to the Mensheviks subjected to repressions under Lenin that he did not agree with their ideas at all, but he would shake hands with them, not with the "Bolshevik scoundrels."
Bordigists (Italy)
Bordigists are very different. They are the supporters of Amadeo Bordiga in the Italian Communist Party. They were also very influential in those years in Italy. Bordigists supported the authoritarian centralized party and trade unions. They were not opposed to councils, but, like the Leninist Bolsheviks, were in favor of a command centralized control system of the councils which had to be carried out by their party, that is, the power of the minority party and not the workers themselves. At the same time, Bordigists argued that the Communist Party was the bearer of absolute proletarian communist truth and better than other workers knew what the working class needed, even if the Communist Party united a minority of workers. That is, they did not much differ from Leninism (although among them there were some non-authoritarian currents, close to the German- Dutch council communism – followers of Onorato Damena, for example).
In other words, the term "left communism" is quite pointless and unsystematic, representing completely different ideological currents with opposing views.
Socialism or Barbarism
Once they all were mighty (at least, when applied to Germany) political movements. Then, with the slowing down of the revolutionary mass movement, they turned into tiny sects. The last of the interesting groups of council communists that provided some intellectual influence on mass social processes were the French organization ‘Socialism or Barbarism’ (1948-1956), and situationists. Although the former had no more than 100 people, it had among its members such outstanding representatives of socio- revolutionary thought, as Cornelius Castoriadis ( the adversary of historical materialism), Guy Debord, leading situationsit theorist and the author of ‘The Society of the Spectacle’, a social thinker Claude Lefort, and others. The ideas of this group, especially those of Debord, influenced the French May, 1968. The ideas of the councils, workers’ autonomy, their independence from the parties, direct proletarian democracy, the rejection of the trade unions and the state – such were the foundation stones of the group.
Another important thing. Council communists and Bordigists were Marxists. But already Rühle began to depart from pure Marxism. He believed that the victory of Nazism in Germany could not be explained by economic factors alone, and became one of the first proponents of Freudian Marxism, Marxism and psychoanalysis compound. "Socialism or Barbarism" went even further. Although there were also followers of pure Marxist philosophy, Castoriadis and Debord went quite far away from the Marxist orthodoxy. The former rejected historical materialism, claiming that economic and political relations represent not the basis and the superstructure, but a continuously interacting chain of events in which it is impossible to distinguish the primary element. The latter was carried away by the idea of the "society of the spectacle", describing capitalism as a system of attractive fetishes, small and large spectacles (from the brand of soap and its advertising to modern warfare) that are worshiped by mankind .
Crisis
Since then, no influential groups of council communism (not to mention left communism) appeared. There were smaller sects, trying, for example, to combine Bordigism with council communism (which in fact are totally incompatible), or create something of their own. In my opinion, they are not interesting to consider because of their small size and lack of any real social impact, the isolation of their ideas from real life and their scandalous behavior. The latter is probably the result of their abode in the narrow and musty sectarian little world.
Future
I’d see the future in an attempt to create a movement or group, or an organization such as ‘Socialism or Barbarism’. That is, the synthesis of a wide variety of anti-authoritarian currents of socialist thought (from Isaac Steinberg to Carl Roth), council communism and anarchism. Such a group could try to play a role similar to that of ‘Socialism or Barbarism’. Today, nothing like this exists. But it certainly will not be left communism. Like I say, the very term "left communism" is meaningless.



Can comment on articles and discussions
A couple of previous threads on this perennial favourite
The differences if any between Left-Communism, Council Communism and Bordigism. (2009)
Left Communism and Bolshevism (2006)