Geoff Cohen's nailed a really important idea about network effects in "groupware," and the way that groupware creates group-think:
…it's a little applet which displays a bunch of pixels in a rectangle. Instructions tell the user that the area ought to look like a world map. One pixel is highlighted, and a form asks if the highlighted pixel ought to be land or water. Rinse, lather, repeat, and ten thousand visits later or so, it's moved from random noise to a recognizable world map. Pretty incredible…
Furthermore, imagine the difficulty of changing that consensus. Maybe you're a Pacific Islander, and you want to change the map to reflect the actual size of the Pacific. Too bad! Given the momentum of the consensus, it would be prohibitively difficult to move all the pixels of North America over the east, or shrink Asia, or whatever it would take. For the architecture of this application, consensus is what the old chaos mathematicians would call an attractor, and it's a powerful one.
