Firstly a community will have a widely agreed upon public goal like to raise a certain amount of money by a certain time for a certain reason.
Communities will have means of communicating with it’s members like telephones and email.
A community uses what the members participate in as a means of finding information and feed back like seeing who bought tickets for local events.
Communities have and use a number of ways to communicate the aims that the community wish to further. For example, advertising is way to communicate ideas of the group.
In addition, communities will have own individual characteristics about them like sports teams or special monuments.
Finally a community will have a certain number of members with a certain level of skill and expertise for the community. This can be like a child learning from their parent.