• by Wendy Davis , Staff Writer @wendyndavis, July 10, 2015

Thomas Dart, the crusading sheriff of Cook County, Ill., recently protested online sex trafficking by asking Visa and Mastercard to stop doing business with the listings site Backpage.com.

The credit card companies acquiesced; last week, they stopped processing payments to Backpage.com.

The move reportedly left Backpage users with no way to pay for its controversial “adult services” ads, except for Bitcoin.

But Backpage responded with a decision that probably surprised Dart: The company is letting people temporarily post free adult services ads.

Backpage's move likely won't last forever, says Peter Zollman, founding principal of Advanced Interactive Media Group. Still, he says, the gesture demonstrates that Backpage won't let outsiders set its policies.

“I don't believe they could make a long-term business without the revenue from the adult services ads,” Zollman says. “In the meantime, maintaining an audience, and showing an ability to get around the sheriff's edict, is important to them.”

Zollman also points out it's a lot easier for law enforcement personnel to discover the identities of Backpage's users when they pay with credit cards than than when they use Bitcoin, or post for free.

In fact, he adds, Craigslist only started charging for adult services ads after a coalition of attorneys general specifically requested that the company do so. “What's so ironic is that the attorneys general desperately wanted Craigslist to use credit cards for its adult services ads, so they could track the people involved,” he says.

Craigslist eventually stopped allowing ads for adult services on its, but the ads didn't disappear. Instead they migrated to other sites, including Backpage.com.

Since then, Backpage has drawn much criticism for allowing sex ads, and has been drawn into several high-profile legal battles over them. To date, Backpage has prevailed in all of the courtroom fights.

Most recently, this May U.S. District Court Judge Richard Stearns in Boston threw out a lawsuit against Backpage brought by three teen sex trafficking victims. The teens said that Backpage.com facilitated the crimes committed against them. But Stearns ruled that the federal Communications Decency Act provides that Web sites need not police posts by users.

Meanwhile, Massachusetts Attorney General Maura Healey this week publicly urged Backpage to stop accepting adult services ads. Her call came after a prostitute was murdered in a Boston hotel, allegedly by two people who used Backpage's listings to rob advertised escorts.

But experts like Zollman predict that if Backpage.com stops accepting the controversial adult ads, they will almost certainly resurface on other sites. He adds that even if every company based in the U.S. stopped accepting the ads, they probably would migrate offshore -- which would make it difficult, if not impossible, for law enforcement to investigate users who commit crimes.