Women/people are anonymous on the internet.
There is no reason for them not to spill their guts regarding their desires.
This doesn't concern purely sexual or fetish matters, but from conversations and exchanges with friends, I have the impression that women are more wary and distrustful (and lacking knowledge of) the Internet, computers and how it all works. I often hear the silliest scare stories and absurd misconceptions from ladies. And I am talking about friends of mine, virtually all U graduates like me. But for some reason they have a (minor to large) aversion to trying to even basically understand the workings and limitations/possibilities of IT technology and so end up buying into the old canards circulating.
Which translates into them certainly not being willing to spill their guts and desires anywhere on the Internet. Because ultimately they believe they are not anonymous. To be fair, the printed media and television and entertainment does not help them learn any enlightened and correct views on the matter. The scare stories printed in newspapers are often absurd.
And also some are sort of goody-goody about Internet related matters. When it comes to Facebook (whatever your opinions are, positive or negative) I hear some utterly ridiculous talk from women on how they think it works, especially all the horrid, invasive things that can happen if you join FB. Talk about being paranoid. And nothing you explain can convince them otherwise.
So while in real life you can be anonymous on the Internet, many women do not believe that claim.