http://motherboard.vice.com/read/sex-workers-guide-to-bitcoin
"Recently, VISA and MasterCard pulled out from Backpage.com, the second largest online hub for classified ads behind Craigslist. That left Bitcoin (and two other cryptocurrencies, Litecoin and Dogecoin), as the only way for sex workers to pay for listing their ads.
"This is obviously an awful situation," Liara Roux, an escort based in San Francisco wrote on her website in the preface to one such guide, "many sex workers rely heavily on Backpage for their business. While it would be wonderful to have a magic wand and fix this problem, bitcoin is one of the few payment methods still accepted by Backpage and I want to make sure those who need it can use it."
This is the kind of politically orchestrated faux-moral douche-baggery that drove the US authorities to pressure Visa, MasterCard and Amex to cease supporting contributions to Wikileaks. Restraint of trade, period.