Somewhat related: A couple years ago my buddy and I had read an article about how profitable dating sites were, so we looked at some of the more popular ones (on the top grossing iPhone store) to see what the user experience was like. The idea was that we would gamify the experience, helping the betas actually get past the initial awkwardness of introductions and getting-to-know you. If we could actually get these typically unsuccessful dudes out on dates we figured we'd be looking at some big bucks.
We got to work right away and split up our research efforts. I won the coin toss so he took Match, Scruff, and Grindr (gay male Tinder, essentially). This left me Zoosk, OkCupid, and Ashley Madison. I knew within a couple hours that AM was a scam because I wasn't bothering to put any actual details in my profiles I was making (after all, this was just for research on the user experience - finding other users, interacting with them, etc).
Anyway, I received my first message within a couple hours of creating the profile. I received a second message a few days later. Remember, I don't have a picture, and I don't have any details in my profile. Of course, to read messages you must be a subscriber. Out of curiosity, I look to see how much it would cost me to actually read the messages, and it's something like $40 for 30 days.
At this point I'm thinking, "How are they getting away with fake messaging their users?" I look at the terms of service (possibly for the first time in my adult life) and see - in small print of course - that they will message users from time to time so that they can "experience interacting with the message system"... or something like that.
So yeah, 90-95% of the female profiles being fake is absolutely not a surprise to me.