announced it would no longer cover transactions from adult sites. According to the committee to Study Tools and Strategies for Protecting Kids from Pornography and Their Applicability to Other Inappropriate Internet Content, there are over 100,000 subscription sites with adult content in the United States, with each site having multiple web pages. On average, a paid subscription generates $20 to $40 per month in revenue, however, an in-depth analysis is complicated. If a visitor site connects to a pay site and signs up for content, it receives a conversion fee from the larger site. A successful large operation is often an umbrella company serving many markets with pay sites. Around this core and its affiliates is a system of ad-supported service sites. The so-called portable porn market is in its initial stage in the U.S. In 2000 the owners and operators of Playgirl.com and scores of other adult sites were charged by the U.S. Federal Trade Commission with illegally billing thousands of consumers for services that were advertised as free, and for billing other consumers who never visited the web sites at all. Nevadan Voice Media Incorporated, which ran several adult sites, was also charged by the commission. Sites often suffer from unauthorized, non-paying surfers who use stolen passwords, which can use month's worth of bandwidth in a day, costing the site operator hundreds or thousands of dollars' worth of additional bandwidth fees, all for traffic that returns no money at all. The 2002 Paragon Electric Co., Inc. v. Buy This Domain case ruled that linking domain names to pornographic sites is not per se conclusive of bad-faith registration and use, although it does raise that presumption. A common occurrence was the use of domain names similar to known ones, such as whitehouse.com (unrelated to whitehouse.gov), which for some period featured explicit content. The use of expired domains is also common, along with typosquatting, which relies on mistakes such as typos made by Internet users when inputting a website address into a web browser. Economics In 1975, the total retail value of all the hardcore pornography in the U.S. was estimated at $5–10 million. The 1979 Revision of the Federal Criminal Code stated that "in Los Angeles alone, the pornography business does $100 million a year in gross retail volume" while "the average pornography magazine sells for between $6 and $10 each". According to the 1986 Attorney General's Commission on