A final comment on an interesting story on the growth rate of wikipedia caught my eye;

"In my experience, the only thing we've seen these growth patterns [of wikipedia, in] before is in population growth studies – where there's some sort of resource constraint that results in this model." The site, [Ed H Chi, a scientist who works at the Palo Alto Research Center] suggests, is becoming like a community where resources have started to run out. "As you run out of food, people start competing for that food, and that results in a slowdown in population growth and means that the stronger, more well-adapted part of the population starts to have more power."

Which looks like...

There is also more on this story here.