This page is intended to be used by employers, so I've moved the content that's not really aimed at them into the talk page.
Sexism and Networking Content
Networking is important in this day in age, where it's not what you know but who you know. Unfortunately, something as seemingly simple and easy as knowing someone may be fiendishly challenging. It may be hard for men with male privilege to notice, but word-of-mouth job advertising may not reach women. There are male employees that do not see women as equals and peers, interacting only with women when they want to achieve a sexual goal. Telling these male employees to spread the word about job opportunities will only gain you more male job applicants as the majority of women are shut out of this "hidden job market."
The only time a woman may hear of the job opportunity is if she is a current girlfriend of one of these sexist male employees. You will only reach one prospective female job applicant per male employee this way, if he's (1) dating at all, if he's (2) attracted to her sexually, if he's (3) heterosexual, if she's (4) heterosexual too, if (5) the person he chooses to date happens to be a qualified technical woman at all, rather than one of the more numerous non-technical women out there. Those are a lot of if's filtering out potential female job applicants. These female applicants may also be filtered out based on race, disability, size, or age, on top of gender and sexual orientation, all based on the male employee's personal dating preference. Scores of highly qualified women may never know of your open job position just solely based on the fact that they are women and cannot simply befriend the man as if they were other men.
To gain access to your job openings, they would be required to individually be in a relationship with one of your male employees or, absurdly, be in a relationship with him all at the same time. For this reason, you should never rely solely on word-of-mouth hiring if your intention is to recruit a meaningful number of women. (This Wikia contributer has been repeatedly denied connections to the job market because a male IT employee simply claimed, "I'm not looking for friends, sorry," when he was diplomatically turned down on a relationship in place of friendship instead. He then cut off all contact unless a romantic relationship was offered in return, nullifying any possibilities of employment through him.) Networking in technical fields especially may be difficult for women due to two compounding reasons: (1) the majority of technical employees being male, and (2) the intense sexism existing within geek culture. To recruit women, get rid of their reliance on industry gatekeepers that hold hostage information on jobs. Until sexism in the geek community changes, you'll need to diversify your recruiting methods and make them more transparent and accessible.
Merit based evaluation
(I've moved this content here too, because it doesn't apply in all cases, or in all juristrictions. In particular, not everybody is offered the same opportunities at uni)
Also, try to use a merit-based evaluation process. Write your ad in such a way that it places value on aptitude and skills rather than membership in a particular club or social class. Placing emphasis on school GPA is one way of promoting meritocracy. In school, students of both genders get access to the same professors, technologies, and controlled learning environment. Outside of school, things are different. Hacking groups and open-source communities can be inhospitable to women. In school, professors are paid to educate and answer any questions on the learning material, providing assistance if students are stuck on difficult problems regardless of the gender or background of the students. Thus, comparing candidates based on college performance is equitable and accurate. Outside of school, women trying to learn how to code can be met with hostility, or they can be outright ignored.
If your job ad is written in such a way that it values open-source experience over GPA, you run the risk of measuring your candidates not by real aptitude but by their ability to navigate through an unregulated learning environment biased in favour of its male participants. It is understandable that some companies value open-source experience because it is evidence of motivation and independent learning. However, just be aware that the results of that independent learning experience may vary from gender to gender due to the additional barriers that women face. There is no rational reason to value open-source experience over college-measured aptitude because women that have picked up old programming languages at school can be simply trained to adopt new programming languages on the job. By valuing open-source experience, you may identify some motivated male job candidates that are fortunate and privileged enough to have spare time to hack with. However, you will be missing out on a lot of female talent. Offering internships and job training based on college GPA is more equitable than expecting women to keep on top of current technologies outside of school on their own, without mentors.