A lot of blame has been put on hot chicks in video games. The conventional wisdom is that women don't play video games because they're alienated by portrayals of women in video games. I think this isn't *entirely* accurate, or at least, it isn't the whole story. There's a reason that magazines targeted at men and at women both use hot chicks for their cover art.
But I digress. For some people, it may well be that the avatar does impede the gaming experience. I admit I'd have a hard time identifying with Duke Nukem; but maybe not so much with the Master Chief. So let's look at ARGs from this perspective of avatars.
That doesn't get you far, at first, because in an ARG, you have no avatar but what you make for yourself. Most people play an ARG as, well, themselves. Some beautiful, creative souls play as noir detectives or military personnel from previous games. This means both men and women are free to construct their game personalities however they choose to participate. ARGs aren't the first genre ever to do this, of course; I've been playing avatar-free games forever (Carmen Sandiego on to most-but-not-all Infocom titles on up to SimCity 4). It's nice to feel free to be yourself.) But this no-avatar bit, it runs deeper than a first glance might show you. It's got some far-ranging effects.
This ties into an old trick novelists use to help their audiences identify with a protagonist. Describe the hero or heroine as sparingly as possible, and reference that description as rarely as possible. The reader's imagination will then automatically fill in the gaps to make that character a sympathetic one.
To get sidetracked again for one minute: The fun thing is, in an ARG, that trick transforms itself to apply to other characters, too. In the AI Game, there was a character called the Red King. His name was Dwayne, as I recall. We knew he was a teenaged boy, but beyond that, his physical appearance was largely undescribed. The Red King became one of the most sympathetic characters in the entire story, and I think this was no accident. This is the magic of letting your audience fill in gaps, a luxury that video games with their ever-more-realistic graphics and voice acting can never do. This is also why a good horror director never shows you the monster; what you come up with on your own is your personal scariest-possible scenario. Ahem.
So this is my step one in what makes ARGs so woman-friendly. In an ARG, there's nothing on screen constantly reminding you that you weren't the target market. Step two: Realistic female characters, coming up next time.