Wiki Community is more like our human world - open to change, which is the spice of life. The changes may be good or evil, depending on one's viewpoint, but only the most suitable will prevail. This is what nature is all about. -- Raj
A bunch of human beings communicating via a shared notepad. Nothing to do with a Wiki Mind, whatever that might be.
A different view: the Wiki Community consists of all collaborating (human or non-human) Wiki Agents. -- Fridemar Pache
Clay Shirky has a very interesting article on the difference between communities and audiences. The quickie summary is: audiences scale, communities don't.
See shirky.com 
On Participation
From Clay Shirky's Web pages: "communities have strong upper limits on size, while audiences can grow arbitrarily large."
The Wiki Community, however is not composed of each and every member interacting on each and every point. Since interaction is possible by every member on every page, but is practiced by only about 1/70th of the members on a limited number of the pages, the potential of the community is greater than one might think.
The Wiki Community is composed of audiences as well as participants. Taking that into consideration, it can be said that while communities don't scale, audiences and wikis do.
Wiki Readers , people who read but do not contribute, need to be recognised as "extended family". Their "invisible and indirect" support enable Wiki Zens to engage in Barn Raising activities.
A most striking example is Wiki Pedia, a much larger community access it than the few who labored through its content and presentation. And without the encouragement from the larger community, Wiki Pedia Regular Contributors would wither away.
See Bot War for an example of the Wiki Community at work.
See original on c2.com