Sex is big business. The porn industry's main trade publication, Adult Video News, estimated global 2005 sales at $12.6 billion. But that figure is difficult to verify because porn companies are private and closely held. As with Hollywood, DVDs account for the largest piece of the porn industry's revenue — 34%; for mainstream studios, they account for nearly 50%.

Porn producers say changes in zoning laws around the U.S. have forced adult movie stores to the margins of commerce — usually in industrial or commercial zones — pushing more consumers online for their flesh fix. The Web offers a cornucopia of content without the stigma.

"Three years ago, DVDs were responsible for 90% of our income," said Vivid's Steven Hirsch, who founded the company in 1985 with David James. "This year, it will account for 30% of our sales. With the Internet there is no distributor between you and the consumer, so you can keep a larger part of the revenue stream."