Some anarchists view anarchism as the end state of communism without the interim of a totalitarian regime. Basically that means a governmentless society in peace and harmony with brother man in equity and cooperation. Whatever the faluts or virtues of such a theory there is reason to stop at the very first step, the notion of an ideal society.
Why should we ever be in the business of an ideal society at all? The problems such theories are trying to address are not ideal but rather practical. Why not offer solutions from the perspective of the problems themselves. Namely if I do X, Y will be solved, and that moves me to Z. The ideal society say in such and such conditions Y will not exist because of such and such social structures. Now there is some validity to this move in so far as a theorist wishes to justify their practical solutions. For example someone wants to change the produce in their grocery store to all organic. So they say "I want to change apples to organic, oranges, beets....." Someone might ask why. One answer might be "The store will reach a broader audience and further the health of its customers". The answer uses an ideal, that of the future ideal store with healthy products, more customers, diversity, etc., to explain the changes sought. It is another thing all together to begin with an idealized society and attempt to derive one's current practical reforms in accordance with such. I believe this is why many leftists tend to believe revolution is the only vehicle of change. For it is inconceivable that the current society could ever adjust to the ideal by anything short of total revolution. Even with the various revolutions we have seen there has been great difficulty changing the social institutions to fit the ideals of say communism. Much of these difficulties are due to issues in the structure of the theory itself and couldn't be worked out until people were able to test it.
So those are some reasons to worry about appeal to ideal or utopian societies generally. There are other like the fact that utopia sounds fairly boring or frightening but I will set those aside. My claim is that anarchism need not be a utopian theory.
Begin with the thesis: Whenever possible and to the greatest degree possible, breakdown hierarchical state structures and construct participatory and equitable social institutions. My reasons for finding such a view appealing are that in a society which must retain its hierarchies, the best, brightest, and wisest will be kept down by inferior superiors attempting to keep their thrones. Thus anarchism ought to strive to allow all its members to developp their abilities and intellect as far as they will to go. One might also cite love of justice, quality of life under a society in which the majority is used as a means to the ends of unintelligent, and base leaders.
From this thesis one can see how anarchism might work. Whereever you are and hierarchy is unjustified, one ought to replace it with a democratic participatory structure. There are justified hierarchies and authority (that is why the term anarchism is annoying). For instance moral authority might be justified, familial authority or authority over those who cannot take care of themselves is justified, etc. The structures I have in mind are somewhat like City Bikes, the IWW, RED & Black Cafe, etc. That is groups of people who manage themselves autonomously and take on the tasks and profits as a group. A larger structure would be a freely organized federation of such groups who come together to organize and develop some greater service. Say a steel production syndicate establishes a federation with worker self-managed miners, truck drivers, plants that produce steel based materials, etc. They might band together and utilize group profits to develop the poorer plants, develop production technologies, etc. On the larger level things get slightly more complicated and I would want to bring in Participatory Economics and more ideas about industrial unionism and federations. Nevertheless there are current examples in effect on the small scale in portland, and at the municipal level in Brazil, and Spain. Not to mention historical examples.... Tell me if you want me to continue.