The effect of a man’s facial attitude
OKCupid has posted a statistical analysis of profile pictures, which probably applies for Facebook. Apparently webcam flirty faces are effective, it’s better for men to not smile, and showing a bit of cleavage or abs doesn’t hurt. These are typically viewed as gauche practices online, so the report is titled The 4 Big Myths Of Profile Pictures. Myth number 1 is that it’s better to smile, myth 2 is that webcams are bad, myth 3 is that showing body is good, and myth 4 is that not showing face is fine. According to this my ideal profile picture should be a shirtless webcam shot, unsmiling and looking away from the camera.
The effect of a woman’s facial attitude
In short, like in real life, openly flirting will get you more attention. Flirty for men takes a more indirect route, but still sending the same signals. Even though the practice often looks damn stupid frozen in time, it’s seemingly still effective. The report is worth a full read. It has pictures and graphs.