Usage Of Flash To Recreate Deleted Cookies Minimal

The good news is that zombie cookies -- deleted HTTP cookies that have been resurrected through Adobe Flash Local Shared Objects (LSOs) -- are rare.

The bad news is that lack of visibility into Internet marketers' tracking practices makes self-regulation a dubious strategy for averting potential privacy problems.

A study published on Monday by Carnegie Mellon researchers Aleecia M. McDonald and Lorrie Faith Cranor, "A Survey of the Use of Adobe Flash Local Shared Objects to Respawn HTTP Cookies," has found that misuse of Adobe's Flash technology to rebuild deleted HTTP cookies isn't as widespread as some have feared.

LSOs are Flash's version of HTTP cookies. Few computer users are familiar with them but they present even greater potential for privacy problems because they can be read from any browser, because they're don't expire, and because they can store more data and more complex data types than HTTP cookies.

Because they can be uniquely identified, LSOs present similar privacy problems to cookies while being less affected by user choice. As the study explains, marketers turned to LSOs to address the data quality problems created by the deletion of cookies by Internet users. But doing so flouts users' expressed desire for privacy.

The researchers found no evidence of cookie respawning at 500 randomly selected Web sites and only two instances of resurrected cookies at the 100 most popular Web sites. They also found that LSOs were being used as unique identifiers at 9% of the most popular 100 Web sites and at 3.4% of the 500 randomly selected Web sites.

"We found respawning is currently rare but sites still use LSOs as persistent identifiers..., which may or may not have privacy implications...," the study states.

The researchers suggest that Adobe should take a more proactive role in making it clear that LSOs should not be used to uniquely identify computers and in providing developers with strong privacy guidance and tools. The researchers claim that just over 40% of sites save LSO data, which they interpret as a sign that Flash developers may not understand the privacy implications of LSOs.

They also express skepticism about the ongoing viability of self-regulation. "It is difficult to find calls for a purely industry self-regulation approach to Internet privacy credible when industry demonstrates willingness to violate user intent and privacy as demonstrated by using LSOs to respawn HTTP cookies or individually identify computers," they state.

With the Federal Trade Commission mulling privacy rules after years of hands-off policy, not to mention a slew of recent lawsuits over alleged privacy violations related to tracking, the era of lightly regulated online marketing may be coming to an end.