According to a study by Stanford University Law School's Center for Internet and Society, many online ad networks push out tracking cookies even when users say they don't want to be tracked.

"Half of 64 online advertising firms did not remove their tracking cookies from consumers' computers after they have opted out of behavioral ad targeting," writes Threatpost's Paul Roberts. "Twelve percent of those firms failed to remove tracking cookies, or continued to place them on consumers' systems even after those consumers opted out of tracking."

"The study, which was carried out over several months by researchers at the Stanford Security Lab, suggest that voluntary, industry led efforts to reign in unwanted user tracking online may be falling short," Roberts writes.

Go to "Study Finds Online Ad Firms Don't Abide By 'Do Not Track' Requests" to read the details.

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