BeiYin: All this talking is about  theories and also talk about 'substantial researches'. What does it mean that an IC has 'succeeded'? That they started an 'IC'? Then they succeeded to live together, but for how long? If they succeeded, then they succeeded to grow in number? They attracted other people? So then why they succeeded? What was the living form of these IC's? How did they solve their problems? Probably they run their 'IC' like a business or a coop or sharing houses or they run their 'IC' like an ashram. What about rules? When people come together to share their dreams and hopes,  then from where they are coming? They don't just meet in the street or in the pub and then they start to dream together, so they are already in a certain setup, what is this then?

Comment:This may seem trivial, but when  a group of people can share and discuss their ideas about what kind of community they want to be a part of, it can bring them together.

BeiYin: Yes, ideas and common concepts can bring people together and they can confirm each other in their ideas. These kind of discussions can be creative, although they are mainly used to confirm each other or to find and strengthen one's position by fighting against the other opinions, -  who is the strongest wins... 
(Observe the Usenet: Years ago all news groups were full of discussions and in parts quite creative and interesting. This were slowing down more and more and now nearly all news groups are dead. The same seems to happen with mailing lists and message boards, they are slowing down more and more. Just look at this one: There are hardly any responses and the level goes down. I still believe we can use the opportunity for an exchange, although I am starting to get tired of all the nonsense and low level comments...)
All these discussions are useful up to a certain degree, but then when it comes to live these beautiful dreams and convincing concepts, then the difficulties start because confrontation with reality will happen. Reality of this world and reality of the individual, with all their different conditions clashing against each other. The coming together then on a daily life level will cause the problems. People are mostly lacking the right tools to deal with these daily difficulties appearing in living together. They succeeded to come together - but for how long? The research will tell that this is about two or three years and then the group will fall apart. If there is a leader, then it will last longer, if the leader is strong enough with a very sophisticated concept, then it will last maybe even twenty years and you might call this successful. So what does it mean that the group 'succeeded'?

Comment:Of course some members of such a group may disagree and that minority will go their own way, perhaps found a separate community. 
The important point of this is that the people work and talk and think together and in doing so, already begin to feel themselves to be a part of a community. 
And without some input into the foundation of the community, a lot of 
people will not feel a part of it.  Indeed, even established ICs can begin to lose their "glue" - their feelings and culture of togetherness - from time to time and need measures which will bring them together again.

BeiYin: If the 'important point' is limited to the talking, working and thinking together and that out of this they are getting their self confirmation and their feeling to be part of the community, then this group will not last long, unless there are another goal which holds them together. This might be material or spiritual. Then this group might stay together longer, although with quite a lot fluctuation. You might call such an 'IC' established and if it starts to fall apart - losing their glue - then that it goes on they can ad some 'measures' to bring them together again. What might this be? If it is a material orientated community then some spiritual concepts? I think this is interesting and needs to be explored a bit more in depth. You say: 'Without some input into the foundation of the community, a lot of people will not feel a part of it.' You are right, but what is the 'input'? Ideas, dreams, money? Shouldn't be their interest to be part of it with their whole existence, their motivation, their initiative, their daily input of work, their awareness, their love - be enough???
Isn't the most important point that people *grow* together? That they live in a setup which furthers this? In a world which is mostly materialistic orientated, so living together with 'kindred spirits' makes living together more creative?