Yoiks! I got distracted in that other posting. I asked the question—why are there seemingly so many guys whose primary avatar is female?—but didn't really even attempt to answer! I appreciate the comments that entry has already received. Comments always provide additional insights. Maybe there will be more insights from this one.
I already touched on one reason that some men play women. It's more social than sexual. For all the talk of male bonding, it's women who bond more easily. Women tend to see each other as allies. They can form exclusive cliques, of course, but in general they are more welcoming. Women can form friendships at any point in their lives. For men, not so much. Heterosexual men might have other men they hang out with—go to bars, watch sports, shoot hoops, things like that—but they are rarely close to other men unless they happen to have known someone for a long time, like an old buddy from high school or university. Women can more easily get close to other women, and can share much more intimate things than men can with each other. When it comes to friendships, woman are freer than men.
Another reason is that women, much more than men in this society, can be overtly sexy. They are allowed, even encouraged, to put their wares on display. It's like the opposite of the situation among birds, where males tend to have the brighter plumage and are the ones that "strut their stuff" (and females do the choosing). Among humans, with some exceptions, that's the domain of women. Women can strive to look beautiful. Men get to be strong silent types. They can be rugged and handsome, if they're lucky, but they're supposed to do that without making much effort. If they make too much effort, that's not manly. So here again, women are allowed more freedom than men.
(Incidentally, this freedom to be sexual is very powerful. I think it's one of the reasons for the oppressive patriarchy, and why in some societies women are forbidden to make any kind of display. A woman can bring the strongest man to his knees just by being herself. Desire can sap the will out of the toughest guy. This leads to men both wanting and fearing women, which of course leads to a desire to control. You know the rest.)
Second Life, of course, helps with this freedom to preen and strut. SL is loaded with "slutwear." But it's not just that. Designers also create very beautiful clothes, not just overtly sexy ones. Female avatars can as easily look beautiful and sophisticated as hot and sexy. The range of female clothing is astounding, and new designs and designers keep on showing up. For men, the choice is limited, although not as limited as many think. Still, just as in first life, guys don't have the clothing options that women do. Women have the freedom to look beautiful, sexy, sweet, pretty, or any and all of the above. The range for women even includes most of the range for men.
It's clear from comments I have read that being female in SL is liberating in these ways and more. For some, being female allows them the freedom to open themselves up, to be vulnerable, to learn about their own emotional range. They don't get this in their first lives. The fantasy of SL, the allowance for imagination, lets them escape the chains of first life male existence. They seem to be better men for it. And some question whether they have been repressing something in themselves.
What we're seeing in SL is that many more men than might have been imagined, when given the opportunity for a fantasy existence, choose to be female. This is extraordinary. It's telling us things about what men want when given the chance. It's telling us about what is lacking in men's lives in the our current cultures. It's like a grand social experiment, although without controls. Still, someone in academia should probably study what's going on here. No doubt there is much more to learn.