Quantcast Website Traffic Data - How Do They Get It?
I was recently looking into Quantcast to have a couple of my sites tracked for traffic data to reach more advertisers.
Before I created an account, I checked to see if my sites were already listed. One was not. The other was not only listed, but the results indicated it was "Quantified" with "Directly Measured Data". I had thought this was only possible if you registered with Quantcast and added their script tag to your website header/footer.
I double checked my Wordpress setup to make sure no such tags were present. There were not. I verified using "View Source" on the home page and other popular pages and found nothing like a Quantcast tag. I then registered to send Quantcast an inquiry as to how my website was being tracked. There is no support this week, so in the mean time, I added my sites to my new Quantcast account, but did not add their tags to my websites yet. Even Quantcast's site manager says it cannot find Quantcast tags on my websites.
The data they have is actually pretty good and closely tracks the Google Analytics numbers on a daily basis, in a manner that I don't think would be possible with toolbar-based trackers or other estimates. Any ideas how they are doing this?
I can only guess that either Google Analytics, Google Adsense, Lijit/Federated, Valueclick, Wordpress, some Wordpress plugin or my web host (URLJet) are somehow sharing traffic data with Quantcast, intentionally or unintentionally. Any other ideas? Something I may have missed?
My other site is a higher traffic vBulletin forum that is not indexed by Quantcast at all. It also uses Google Analytics, Adsense, Lijit/Federated and Valueclick. I know that hardly eliminates any of those as suspects, but I'm thinking it's more likely a Wordpress plugin, hack or something with Wordpress itself. Less likely is some sort of server software or hack, as my other website is not at URLJet. Maybe something far more obvious that I did, but I can't figure it out. Hopefully they can/will tell me what is doing it.
Okay, from Quantcast, "Wordpress blogs automatically run the Automattic p-code, which Quantifies your site to their Network." I was able to determine that with self-hosted Wordpress installations, this is most likely done via the WordPress Stats (what I have) or Jetpack (newer version) plugins. Furthermore, they don't use standard Quantcast tags, which is why I could find no trace of it. Instead, they disguise them with url shortened links. Perhaps anyone who doesn't want Quantcast tracking or the extra scripts and cookies could completely disable Jetpack/Stats, or maybe it requires additional work to remove it.