Quantcast‘s analytics service has grown rapidly, giving them a footprint (and cookie access) across thousands of websites and 6 billion impressions per day. They recently launched Quantcast Marketer, which promises advertisers “valuable demographic and interest-based insights about their customers as they are exposed to advertising and/or interact with content or functionality on brand sites.” (emphasis mine)
In fact, it looks just like all of the implementations that are collected at the NAI site, although Quantcast is not currently listed as an NAI member.
If I had to guess, I’d say that as Quantcast has moved from simple analytics and into more direct involvement in ad targeting, it has become logical to join the NAI. To be in the NAI, you must offer an opt-out. I suspect that this is still in testing, and the rest of the privacy disclosures are just a step behind. Here’s hoping that those are brought in line quicky and that Quantcast puts a prominent opt-out button on the top page of their site, in the true spirit of the NAI.
Now the critique:
First, the cookie itself does not have a name or text content that clearly identifies it as an opt-out cookie, so it’s hard for the user or researcher to feel assured that the opt-out has been effective. I am guessing that the operative cookie is on the quantserve domain and is called “qoo”, but I can’t be sure.
Second, based on trying this on two different machines, it looks like Quantcast is providing unique cookie text for each opt-out, in the form of a long number. This is poor form, particularly since all the big players (like Google) have moved toward non-unique cookies that, due to their very non-uniqueness, cannot be used for tracking.
One last question for the folks at Quantcast: tonight I also happened to find a Local Shared Object (flash cookie) on my machine from the quantserve.com domain. Are you are using these for tracking or targeting purposes? Will my opt-out be effective for the flash cookie as well?