My legs are massive and I get the "keyhole" type thigh gap. When I was younger and even now I wish my legs would have more of a gap between them, though that's more about their general size and shape. But I have always had really big, legs since being a child even, and when I was a child I was skinny as anything but I still had big thighs. It's just genetics. I'm not complaining, because of the muscle on them they're naturally very strong for a girl which is far more useful than having a thigh gap!
As Lily posted earlier, the picture that Boce had posted isn't the typical "thigh gap", though it's very sexy.
Personally I think all legs are sexy! Marilyn Monroe was actually extremely slim, her measurements were something like a 22 inch waist with a 36 inch bust and she only weighed about 110 pounds in her youth. They say when she rose to more like 130 pounds she was extremely depressed. People always use her as a "curvy girl" good body image, when actually even today she'd be an ultimate "ideal" figure. Tiny waist and enormous breasts! What's different about those times is women would be very slim, but not toned. Exercise for women wasn't such a big thing then, so women would still have the soft bit of fat at the top of their thighs and the bottom of their bellies, making them look a lot more curvy and less slim than today's glamour models. I think the term is now called "skinny fat".
I think that all sorts of shapes of legs are sexy, thigh gap, keyhole gap or no gap at all! As long as the person leads a relatively healthy lifestyle then it doesn't matter!
What I don't like about the whole "thigh gap" thing is that it was created not to appreciate women's bodies, but to diminish other women's bodies, and it is being used as such. The whole "thigh gap" thing is generally pretty nasty in nature, and it is being aimed at women.
I think men will see things like the keyhole gap and think that's sexy and join on the band wagon, but most men don't really understand the difference or what it means, they just see sexy legs. As the video with the highschool girls were saying, most of the boys don't care, it's a female thing which comes from the media and these facebook/tumblr pages. For most guys I think they only like it simply because you have a better view of a woman's pussy from behind.
Recently some people, I think a few guys, decided to do a spoof of the "mind the gap" thing to take the piss and see how long it'd take to go viral called "the bikini bridge" and focused on when a woman is so slim when she wears a bikini the bikini is held up by her hip bones, making a "bridge". It actually went viral and has started to become a "thing". Now I am sure there are plenty of teenage girls looking down as the sunbathe and feeling inadequate.
Eating disorders can do weird things to people's minds. My best friend had an eating disorder as a teenager and she'd look at girls that everyone else would think look disgusting (I mean girls that are beyond just being skinny and look like they should be in hospital) and she'd think they look hot and would want to look like them. Even now she still feels that girls look best when they're around 16 years old, which I think is something that's deluded seeing as she looks far better now than she did when she was 16, but I think she had more confidence then/focused on her looks more. She still gets depressed that she no longer weighs 5 stone... Even though she only weighed around that when she was a child/early teens.
One thing she'd regularly do which I'd tick her off for is she'd go on about how fat she is and how disgusting any body type other than skinny is in front of a group of girls who are all healthy size but definitely bigger than her. She didn't think of it that way, she didn't realise that in insulting herself she was giving twice the insult to those around her. She didn't have a warped image of herself, she knew she was much slimmer than I was/am. I think sometimes those with eating disorders are so focused in beating themselves up and setting these impossible standards that they don't realise it effects those around them. I think this thigh gap thing for many women is the same.