Glad at least we now settled once and for all that it's not "biologically normal" for men to be more attracted to teenage girls than women in their 20s. I've heard that excuse way too many disgusting times.
I get the "taboo" fantasy thing. There are many taboos though - why are there so many videos with "teen" in the title? I mean, I don't get the whole fixation with the "innocence" thing. So many older guys are into virgin young girls (at least ideally), they get turned on fantasizing about "corrupting their innocence" and all that crap. This often translates into dirty old men leering at young women and even worse teenage girls, in real life. Which is obviously disgusting. Is this the way most men think?
I've read somewhere that the term "teen" is often just there to signify that the women in the video have youthful beautiful semi-flawless bodies (which is per se a ridiculous assumption - most teenage girls are far from flawless, their bodies aren't fully developed yet!). So if this is true, when someone clicks on one of the myriad of "teen" labelled videos, what he actually wants to see is a semi-flawless, fully grown woman. Which is once again, actually quite comforting.