Social Democracy is the best attempt at practical socialism tried yet. Well, it seems to be working best, at least.
Far too many of you confuse communism and socialism. I see terms like "workers control of the means of production". The main reasons this happens are:
a) A lot of people like to point out the flaws in communism, which in theory is a utopian society, and in practice can't work in a large "commune".
b) The Soviet and Soviet-upheld regimes tended to tout themselves as communist and socialist, though in reality they believed in the ultimate power of the state apparatus.
The reason communism doesn't work well with a large commune is that a commune works when all members recognize the value of maintaining the well-being of others. For a small commune, the value of others is obvious, especially in the presence of an outside threat. For a large commune, such as a state, individual communities are isolated from each other and informed direct democracy is impossible. Thus, you don't have as much of a say in what you do, and have very little reason to care about how your actions affect the community as a whole.
Game theory is a pretty useful concept in discussions like this, actually - in a small non-anonymous community, fear of societal retribution and emotional attachment can easily make the best decision compliance with a communist system. In a large community, anonymity is easier, so fear of retribution goes down, and the damage to persons you are attached to is spread out onto others, too, creating a tragedy of the commons.