David Sifry is posting The State of the Blogosphere from Technorati's perspective. Precis: big spike in weblogs tracked, lots of spam weblogs detected.
I'll reserve commentary other than to say two things. One, more of these from other institutions would be useful. Some independent verification would be nice. Two, more transparency on how such numbers are derived is sorely needed.
The scientist in me is looking for reproducible results.