This is a November 2008 article in Fast Company by Saabira Chaudhuri, on influential women in web 2.0. It's a U.S-centric list, but an interesting observation is that a significant number of women in I.T. do not come from a techie background. On this list and from women I know personally, degrees in varied degrees like languages, arts and the social sciences feature prominently.
A common trajectory is to have to learn a particular tool in order to get specific tasks done, which leads to an interest in other tools or a desire to learn more to be more efficient. For many women, I believe, getting things done efficiently and effectively, is a priority because the reality is that we are forced to wear many hats in our lives.
Another observation from this article is the hostile reactions it generated from some men, prompting another write-up, Sexist, Sexist and More Sexist, by Ms. Chaudhuri.
She asks where these feelings come from and concludes that the anonymity which the Web offers allows people to say whatever they truly think. And the fact is that, as we know only too well, sexism is alive and well.