I would have to say it is the current financial crisis, period.
I always see people blaming the tubes or people ripping members areas and putting them on file sharing sites.
I do agree the tubes are doing a lot of harm, but people are converting tube ads at equal ratios to any other site. The problem is that no one has money to be paying $30/mo for PORN, and the people that do are the ones signing up.
If the population wasn't so strapped for cash right now we would be seeing amazing numbers IMO. Think about the huge boom of people going online. Even 60+ year old people are emailing and facebooking now.
The only thing I really see wrong with tubes is the fact that they came along at the same time as this financial crisis, which is a major double whammy since they are an easy solution for peoples low funds and their need for a porn fix.
But even still, sales are still there if you want them bad enough. Yeah you can't throw a banner up and make 20 sales but if you know what you're doing then you shouldn't have anything to complain about.
