The Blogosphere's Growth Rate Is Declining!

In his keynote presentation this morning at the Web 2.0 Expo, Technorati's David Sifry presented graphs that imply that the growth rate of the blogosphere is declining. Prior to about six months or a year ago, the data suggested exponential growth for the blogosphere (see Figure 1 below). But in the past six months or so, based on the graphs Sifry presented at the Expo, the number of blogs line appears have changed to linear.

If this is true, then the conclusions in David's April 2006 "State of the Blogosphere" post are no longer valid. Here's what the blogosphere graph looked like at that time:

Figure 1. Technorati "Weblogs Cumulative" graph, April 2006

No More Doubling Every 6 Months

The updated data presented at the Expo suggests it's no longer true that the blogosphere is doubling every 6 months. Like David Sifry, I find data fascinating. If the growth of blogs has switched from exponential growth to linear growth, what might that imply?

At the Expo, while discussing a graph of the number of daily posts (which have changed from exponential growth into more of a slightly rising linear growth -- like a slanted plateau), David suggested that this change may be due to the discovery by people of means other than text for active participation on the Web, such as video. This may indeed be the case.

Unending exponential growth within a bounded data set is impossible. There is a fixed number of human beings, and a fixed number of hours in the day, so the number of blog posts could not possibly increase exponentially forever. Still, it's very curious to see a decline in the growth rate of blogs so early in the history of the participatory Web.

-- Kevin Farnham
O'Reilly Media