How does __utmz survive from HTTPS to HTTP?[ Edited ]
December 2015 - last edited December 2015
Universal Analytics offers no easy way to access information that Classic Ananlytics keeps in the `__utmz` cookie. (Please correct me if I am wrong right here.) The only reason we are still using Classic Analytics is __utmz cookie.
I am currently writing a replacement for this cookie in Tag Manager which works fine… except when it doesn't, like in the scenario below:
1. Search for "a certain keyword" in Google.
2. Click a link to https://www.site.com/
3. Land on https://www.site.com
4. Get a cookie with the value "Source:google,Mediumrganic"
5. Click around the site — the cookie's value remains "Source:google,Mediumrganic"
So far so good.
The script in charge of the cookie is instructed to ignore referrals from our own properties — specifically in order to preserve information about the external origins of sessions.
In the case of "from HTTPS to HTTP", however, the referrer is stripped, so the script correctly labels the visit as "Sourcedirect),Mediumnone)".
Yet the information in __utmz cookie survives the same journey from HTTPS to HTTP.
How does it do it?