How were these particular outfits selected?  The project is very effective at displaying the gendered poses, and the gender binary in where women can "borrow from the boys", but not the opposite.  (By the way, this is perfectly summed by Charlotte Gainsbourg's character in The Cement Garden, made famous in a song by Madonna, What (how?) it feels like for a girl.)  

Where I think the project comes up short is in selecting outfits that do not represent conventional sartorial standards (except for the first image); these outfits are worn by groups where the gender binary does in fact heavily go both ways (although admittedly still permitting more freedom of expression in women).The outfits selected are quite fashion-forward and youthful; I would say they fit into "hipster" fashion, as hard as it is to define.  Such fashion-forward fashion tends to blur masculine-feminine boundaries.  Men may display typically "feminine" stylistic choices such as florals, bare ankles, tightly fitted clothes (like the popular skinny jeans), hair that takes a long time to style etc.; these examples may not as explicitly on a par with the social acceptance for a woman to wear a suit and tie, but they are also not as rigid as the photographs above suggest.

I think the project would've been more effective if the outfits were the right size, and not just switched from one person to the other. The jackets are too small for the men in the second and third pictures, and the hoodie too large for the woman in the last one. That makes them look odd in a way that's not related to gender issues. The issue with gendered poses is strikingly clear, though.
As to Anna's point, I'd think that the fact that the outfits fit into hipster fashion helps get the point across better; even in groups were gender differences are apparently blurred, they are still there.

I find it interesting that when exchanging poses, the couples who are holding hands never thought to exchange the "front hand"-"back hand" dynamic of the handholding. Sometimes it is a question of height (if you're shorter it's easier to have the back hand because you can bend your elbow), but even with same-height couples the man almost always has the front hand. And I find it makes a significant difference in who appears dominant. Funnily enough there is a couple (maya & graham) where the girl has the front hand, but they also forget to change it!

With regards to the poses, I actually think it's more telling how uncomfortable the men are in trying to (and usually failing to) emulate the women's poses. In every switched picture, the women are emulating the men's poses almost perfectly -- that is, without any noticeable "errors" -- and they look natural when doing it. But the men look very uncomfortable when trying to emulate the women's poses, and, strikingly, they are almost all "doing it wrong" (with the exception of the ones on the bright green background, which incidentally didn't strike me as out-of-place, probably because the man in the woman's pose is doing it correctly and comfortably). 

To see what I mean, look closely at the feet and legs of each of the men-in-women's-clothing. In the first set of pictures, the man in the dress is standing with his feet splayed perfectly symmetrically. Notice the woman in the previous picture is leaning slightly to one side, with one foot pointed forward and the other out. In the second set, the man in shorts seems to have no idea what to do with his back leg: whereas the woman in shorts has bent her back knee and touched the point of her toe to the ground in a casual balance, he is awkwardly bending both knees, pushing his pelvis forward, and keeping the toes of his back foot on the ground while distributing his weight, thereby making him look very uncomfortable. In the third set, as I said earlier, the man is correctly reproducing the stance, and he doesn't look uncomfortable or awkward (and therefore, in my mind, not particularly "ooh look out of place gender!"). In the final set on this page, the man in shorts has again missed the mark on what to do with his bent leg. Whereas the woman in shorts has her weight firmly on her right leg, with her left leg bent while facing directly forward and her foot completely pointed (with either the point on the ground or perhaps the whole bottom of the foot leaning against that porch -- it's hard to tell), the man has his leg bent outward, with the foot still somewhat standing on the ground and carrying some weight. He seems off balance and uncomfortable.

I wonder how much of this "incorrect" posing has to do with lack of attention to detail, and how much has to do with learned gender -- learned to the point that the men trying to imitate the poses automatically assume that they must be unnatural poses for men, and therefore don't question the discomfort in the pose. What I mean is, they clearly look uncomfortable, which should be a clue that they're not imitating the pose correctly (since the women don't look uncomfortable in the original poses), but perhaps they think "this is not a natural pose for me, a man, so of course it's going to be uncomfortable" instead of thinking "hmm, this is uncomfortable; perhaps I've put my foot in the wrong place."

Looking through the gallery, it really strikes me how flimsy a summer dress is. The men look practically naked wearing them!

Sometimes, i ignorantly wonder if gendered performace is like language: we learn it growing up, and its *incredibly useful for communication*, even if some people have speech impediments and get mocked unfairly, or choose to speak in non-native language for what ever reason, and are regarded, alternatively, as cosmopolitan or obtuse. 

Weak. The  physical structure of most women and men are DIFFERENT. This includes musculature and bone structure. Therefore, how they move kinetically is tied to BIOLOGY. To pretend that GENDER  trumps BIOLOGY in biological function, i.e., kinetic movement,  is plain silly. You are trying way too hard and undermining the legitimate (but narrow) argument that gender is a reflection of socio-cultural norms. Don't insult my intelligence if you want me to be your ally!

Matthew actually looks kind of badass in the women's clothes. He looks like a samurai with his hair in a bun like that. Toshiro Mifune, maybe.

Just read Goffman's Gendered Advertisement... so many parallels

Another take on a similar theme here:
http://www.jjlevine.ca/switch.html
There is not as great an emphasis on an exact facsimile of the clothes and poses, which gives it a slightly different feel. Also, it is formalwear used, which tends to have a clearer binary associated with it than the outfits above.

Interestingly, for most of the photographs (especially in Switcheroo) I wouldn't have noticed that anything was "wrong" if they hadn't been paired with the "right" photo.

A friend just sent me a very similar post where they're switching up gender and trying out poses from Romance Novel covers.  Good commentary, too. 

http://genrereviews.livejournal.com/377096.html

http://a2.sphotos.ak.fbcdn.net/hphotos-ak-snc7/s320x320/430370_2858684869876_1342260459_32567559_936179559_n.jpg

I would be interested if they took the close the clothes out of it (using somewhat androgynous, though male oriented clothing like the "hipster" style or even better, posing nude) and ask them to pose naturally and then attempted to ask each to recreate the others pose.  The addition of the clothing confuses the embodiment issue for me.

In most of the photos, the women's poses are more complicated than the men's, less balanced, more asymetrical.

I'm not sure if it's just the men wearing feminine clothing are feeling uncomfortable (for various reasons), or if it's just so uncommon to see men posing in such a way that it looks awkward. We're so used to seeing men having more powerful poses that maybe when we seem them in more feminine poses we are reading them as uncomfortable, but they themselves aren't uncomfortable at all? 

Some more images and a note about a similar project: http://blogsareweird.web.unc.edu/2014/02/21/gender-binaries-in-nonverbal-communication/