I can’t vouch for the results or methodology, but there’s a study from Perseus on how many blogs (they say 4.12 MM), who’s starting them, and what their age/gender is. The most striking finding to me: 44% women, 56% men. I’d be interested in a side-by-side comparison to other forms of participation in computing.
actually, Net usage demographics are generally rather gender-balanced. it had been trending upward for the percentage of women, but i can’t find the latest numbers.
January 2002 data from the Pew project had 50.4 percent men and 49.6 percent women among some 2,500 respondents who went online. if anything, the blog numbers surprise me in the preponderance of men — but only because most early-adopting bloggers i knew were women.