The Authority For Television On Demand (Atvod) in the UK has the power to close sites based in the region if they don't adequately control their content. UK law requires that all pornographic websites that a base level of steps to keep under-18s away from porn images and videos.
Tube sites however, are largely located in the United States, and their operation makes it difficult for regulators to police their actions.
Even the old giants of pornography are feeling the pain, with DVD sales plummeting and the days of "big budget" porn nearing death. "Less work comes around because people aren't supporting the porn industry," said Tom Dennis of the Adult Industry Trade Association (AITA).
"They'd rather watch their porn for free then pay for it."
It's not all bad for people in the industry however, with many using Tube sites to advertise their own live webcam services.