Despite the immense popularity that these sites enjoy most of them have yet to make money. The sites are basically run by people who have day jobs and pay for the sites from their own pockets.
During the earlier dotcom boom people found easy money to fund anything they could dream of. In the Web 2.0 world, a few huge $$$ deals have made other sites believe they could strike it big too. The reality, though, is that many struggle to keep the lights on, in the face of growing readership and popularity.
Take for example Asstr, an adult site that is a free, user-supported web site. There are no banners, AVS, blind-links, pop-ups, or other gimmicks designed to pick the reader's pocket. Anyone can submit their erotic stories to the site and people from around the world get to read them.
The site also picks authors who are given space on its server and the benefit is a vast volume of readership yet to be matched by similar sites; all free of cost. I had been submitting my erotic stories on Asstr sporadically and only recently I was accepted into their coterie of authors and collectors. It was a grand experience and I stood in awe of the vistas the site laid open. My stories were read, bookmarked and I even got feedback.
What more could an aspiring writer want? Well, a little money would be nice but when the site itself is struggling to survive its own popularity on overloaded servers and limited budgets, the authors/writers are generally happy enough with the fact that their stories are reaching the readers and some may even become as famous as Kristin Becker.
However, Asstr has been in trouble. Their servers crashed and the site was down for over a week. Management was quick to inform its authors and collectors of the problems they were facing, which were compounded by limited funds. Here is the letter they sent to all their authors and I'm sure it won't be a problem with them if I share it: