Jan 16, 2015 · 1 minute

The decision by some companies to use "zombie cookies" that "come back to life" even after they've been deleted from a computer has come under increasing criticism of late.

ProPublica reports that the Turn advertising company has been using cookies which grab Verizon customers' persistent identifiers -- a string of characters which allows anyone to monitor their Internet usage -- to inform the algorithms personalizing its digital adverts.

The problem comes in when consumers decide to delete their cookies. Turn told ProPublica it doesn't consider the deletion of its cookies an indication someone wants to opt-out of its tracking

So it continues to track them. And even if consumers specifically tell the company they don't want it to monitor their online activities, Turn continues to collect information -- it just purports to stop using the data to personalize the advertisements it chooses to show.

This means an advertising company is monitoring the digital activities of countless Verizon customers, and until the carrier stops using the persistent identifiers, which competitor AT&T did after the so-called perma-cookies attracted criticism, it won't stop.

Privacy advocates aren't the only ones who find this practice problematic. As Jason Kint, the chief executive of Digital Content Next, a trade association meant to improve the relationships between publishers and advertisers, explained in a blog post for Re/code:

This kind of surreptitious behavior does nothing to build trust between consumers, advertisers and publishers, and this trust is what’s needed for fostering clean and safe environments that, ultimately, fund the content of the future. It’s long past time for all industry players to honor Do Not Track signals, which would give consumers a robust, effective and simple way to opt out of tracking.
But it seems unlikely that companies will stop monitoring consumers via obscure tools which follow their every online action. Between perma-cookies, zombie cookies, and tools like the Facebook Atlas platform which follow people around much of the Internet, it seems that near-constant surveillance from private companies isn't going anywhere.

[photo by Mike Mozart]