101,435,253 to be somewhat exact. The good folks at Netcraft posted their November 2006 Web Server Survey, which added another 3.5 million from the month before. Check this out for comparision, "The first Netcraft survey in August 1995 found 18,957 hosts". Talk about explosive growth.
Previous milestones in the survey were reached in April 1997 (1 million sites), February 2000 (10 million), September 2000 (20 million), July 2001 (30 million), April 2003 (40 million), May 2004 (50 million), March 2005 (60 million), August 2005 (70 million). April 2006 (80 million ) and August 2006 (90 million).
Then consider if you counted up the sla.ckers.org board and other places listing vulnerable websites, disclosure might reach 1,000. I also guessed in Dark Reading's "The Web App Security Gap" that maybe 10,000 websites might be professionally tested for vulnerabilities by a third-party. Could lower or higher, but I don't think I'm that far off. Anyway, that's about 1/10th of a percent of the total number of sites out there. That doesn't even qualify as a drop in the bucket. The reality is we really have no idea how secure of (in)-secure the Web is.