I'd say pretty much all of them are aware of this place. If they don't find it themselves, someone in their surrounding will surely come across it sooner or later. But I know a few models who consciously avoid reading their threads, though their family and friends check it all the time.
Working as a model means being in the spotlight, though, and you can't be too sensitive. Yes, most of them ar far from celebrity status, and many of them are very young, but being famous, even if it's in a very limited fashion (no pun intended) always means random strangers will make jealous/thoughtless/mean comments about you.
It's not like anyone's forcing them to visit tFS or similar sites, and this is just a discussion forum on the Internet after all, not much discussion happening if people cannot express negative opinions as well. But there are decent ways to do so. "She's not my type", "I find her way too common", "her lack of expression really bothers me" or "she really needs to work on her walk" are hardly offensive comments. Possibly hurtful, but it's just opinions from complete strangers with nothing better to do, and if you can't handle that, then you're definitely in the wrong business.
But, I'll never understand people calling a girl hideous, fugly, or deformed (I actually saw someone make a comment like that - huh?). Not only is it mean and petty and weird - what happened to a good old "I don't get her appeal because she doesn't know how to pose, and I don't find her attractive either" - but it also makes absolutely no sense. They are models after all...
I'm pretty sure models do read this and I feel bad sometimes when I criticize certain models. I try not to say mean things about models under 18. I know my first experiences with the internet were horrible. I would honestly go to my room and cry when people said mean things about me but now looking back on it it's kind of silly for me to have taken those things so seriously. I think with age other people's opinions of you tend to matter less. If I were a model I would check my thread just for fun.
I'm a models mom and I read TFS all the time, if for nothing else but they post show pics faster then I could ever locate them myself. I think all the models read TFS but take it all with a grain of salt.
Ditto on being a Model's Mom here too - TFA is a great site to see what everyone is doing. You meet a lot of girls in the business and my daughter has found it an easy way to see what the other girls are up to and where they've worked. As far as taking offense to other people's opinions - it's part of the business and accepting criticism is a constant thing unfortunately.