I could write a novel on this subject.
But, as in anything else, take some personal responsibility for staying educated on your site metrics. Track your outbound hits, track your ad views, track your CTR. Tweak, squeeze, massage every penny out of your traffic that you can.
Mix up your PPS and Recurring programs, don't do all one or the other. We're sending checks to people that moved on from our program years ago. Ask Peaches. (when she's ready to be asked questions again)
What Mike AI said was very true about processors, we don't live in a perfect technological world. Things break. Scrubbing is tighter than a prom queen's butt crack these days as well.
If you find the golden traffic, you're lucky. Those are the folks you're after. The people that are surfing, not for porn, but for something else. Then, magically, they wind up at your site by some happenstance. Their curiousity got them off track. Those are the ones that whip out the plastic in many cases.
There's also a shitload of money to be made "in the fringe". That was covered in another thread.
I'm gonna shut up now.