Nielsen Survey Investigates Gamer Choices
Gamasutra reports on findings from a large Nielsen survey on gaming and consumer choices. From the article: "The survey also revealed that 57% of active gamers have played online, with free casual online games the most used, and a notable 21% having played MMO games. While online-enabled console, MMO and gambling gamers are disproportionately male -- 76% vs. 24% -- casual gamers who play free online games such as puzzles are just as likely to be women as men, 49% vs. 51% respectively."
I've noticed from personal experience that free games, especially ones that are easily played for 5-10 minutes during leisure time, are split down the middle for male to female.
MMO's, on the other hand, remain very male dominated. Well, on the surface at least. There might be more women playing than I noticed, but they definitely aren't as vocal as their pseudo-female (Guys with girl avatars) counter-parts.