“The Netscan System provides detailed reports on the activity of Usenet newsgroups, the authors who participate in them, and the conversation threads that emerge from their activity. Using the Netscan tool users can get reports about any newsgroup for any day, week, month, quarter, or year, since September 1999.“
http://netscan.research.microsoft.com/reportcard.asp?timespan=m&searchdate=2/22/2005&NGID=198190&searchfor=microsoft.public.dotnet.framework.compactframework
I've seen this on a couple of other blogs in the past. It has been down for a while but it now appears to be back up.
They now update technical newsgroup statistics daily.