• by Wendy Davis  @wendyndavis, August 25, 2011

Ad network Audience Science revised its privacy policy on Thursday to address how it handles the type of information that Web users might be touchy about.

While the company says it doesn't use "sensitive" data for ad targeting, it also acknowledges that "consumers may have differing opinions regarding which data segments are sensitive." Audience Science adds that it "may use health related segments, such as Cholesterol and Dental, Oral Care."

The self-regulatory group Network Advertising Initiative requires users' opt-in consent for health-related targeting, but only when based on "precise information" about health or medical conditions.

Behavioral targeting itself is anonymous but, as PrivacyChoice's Jim Brock points out, some companies can piece together anonymous information with users' names.

"Once a computer is linked to a health interest through the ad targeting process, that interest potentially may also be connected with personally identifiable information otherwise associated with that machine," PrivacyChoice writes. "While this is not the intention of the ad targeters, it is nevertheless, a consequence of the process."