Dave Sifry, CEO of Technorati, published a report today State of the Blogosphere, April 2006. The number of blogs has been consistently doubling every 6 months for the past 3 1/2 years. Today there are 35M blogs compared to 16M just 6 months ago.

Given the law of large numbers, percentage growth will probably moderate over the next six months. In fact, it already has. I believe there were 27M blogs 3 months ago at the end of 2006, compared to 35M today. In order to continue the streak of doubling every 6 months there would need to be 54M blogs by the end of June. There were *only* 8 million blogs added last quarter so it is very unlikely there will be 19M more added in the second quarter of this year.

The law of large numbers applies to all fast growing companies as well. Google has experienced tremendous growth over the past 4 years, and will continue to grow in absolute terms. But, the percentage growth that Wall Street looks at will decline because the base denominator is getting so big. I wrote "Growing a Google Every Year...4 years in a row" which showed that Microsoft increased revenues by $4B per (more than Google's revenue for the whole year), yet it represented just 10% growth for Microsoft over the previous year. But I digress.

Bloggers are actively posting to these new blogs. About 20M people are still posting to their blogs 3 months after they were created. And about 4M post new articles at least once a week. Technorati estimates that 9% of new blogs are spam, and that 60% of "pings" are from known spam sources. Of course the most popular blogs get spammed the most causing some bloggers to disable comments and trackbacks. There is a business opportunity for an effective blog spam blocker.

Other interesting facts from the report;