On POF, if you're a woman who is fairly average looking, average job, etc, you'll get lots of naice messages.
The more attractive you are (and lets lay the myth to rest, it's got nothing to do with what you're wearing in photos, or what you say in your profile, that's just smug BS peddled by certain MNers who consider the fact they never got an explicit photo as some kind of badge of superiority, I am clearly a better person than you kind of thing
) the worse messages you will get.
I have a friend who did catalogue modelling as a teen and is still very pretty now, albeit in a groomed late 30s way. She got some appalling messages from men while on POF, despite there being nothing provocative about her photos (and frankly even if there had been, that's not an invitation for men to send her disgusting filth) or her profile. I also got my share of vileness, and my block list even after a few days was a mile long. there is something about dating sites which brings out the worst in men, and makes them into some kind of keyboard warrior/pervert hybrid.
There are a handful of nice men on there, but the odds of meeting them are tiny, and it is random - that perfect bloke could be your first date from there, your 1000th or somewhere in between. It's a bit like gambling - the longer you do it, you figure the odds have to be in your favour, but really, as with the lottery, it's just chance.