Good news for child advocacy groups: The Internet Watch Foundation reports a 10 percent decline in the number of Web sites featuring child pornography content worldwide, according to the organization's annual report released Wednesday.

The U.K.-based watchdog group also found that 74 percent of child sexual abuse online could be traced to commercial groups that were selling the illegal images in a total of 850 unique domains, down from 80 percent in 2007.

But 75 percent of those businesses were registered with just 10 domain name registries, which emphasizes the need for such registries to identify and boot the offending domains from the list, the IWF says.

While some countries have debated controversial "three-strikes" laws to cut off Internet access for users who access illegal or copyrighted content, populist outrage has kept such provisions from being signed into law.

And filtering techniques have been known to backfire -- for example, the U.K. blocked the Wikipedia entry of an obscure German rock band because its album cover depicted a nude young girl, which led hordes of users to flock to the site and crash it.

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