Cross Domain Tracking in GA (without cross domain links)

[ketanmv]

Hi everyone,

Been doing some research about cross-domain tracking in Google Analytics (preferably Universal Analytics where documentation is a bit spare). All of the tutorials focus on the auto-linking and ensuring links to the other site are taken care of.

I'm considering a site that may not cross-link like that at all (or it may, but won't be the main avenue). A good example is:

www.gap.com
www.bananarepublic.com
www.oldnavy.com

Now, they do link to the other brands in their navigation but let's pretend that they don't necessarily do that. Gap Corporate may want to roll up all these domains into a single reporting profile because customers can clearly visit any of those sites on their own and buy. It would be nice to know that Visitor X bought 2 items from gap.com and 3 from oldnavy.com... and of course, here were their campaigns, etc. From what I am reading, I am not sure this is really possible. It seems that the cross-domain code is really only best for when my main site links to another domain for checkout or something. But in my example, we are definitely not in control of that kind of behavior.

Thoughts? Perhaps I need to recommend they go with subdomains only which Universal GA seems to handle quite fine out of the box. Thank you!

[S_Curtis]

Google Analytics uses first party cookies to track visitors which means a small text file is stored on your computer associated to the domain of your site. This files stores a unique visitor ID and for security reason is only accessible by the associated domain.

If you want to track another domain, without double counting visitors that go to both, you must use the link code you've seen in GA documentation. What the code does is copy the visitor ID from one cookie under one domain to a cookie under the linked to domain.

Sorry if that was a bit technical but the upshot is: use subdomains, live with double counting or use a web analytics tool that also uses third party cookies as well as first party, such as Webtrends.

[ketanmv]

Just thought I'd follow up after doing a lot more research. It's now my understanding that cross-domain GA will only work if you are moving from one domain to another via onsite links or form posts. It won't do any good if the user visits Domain 1 and Domain 2 independently (they won't look like the same visitor in this case).

If such a thing is required, it seems that sub-domain usage is the only way to account for both types of behaviors (cross domain links and random cross-domain visits).

[ketanmv]

Thanks John - the gap for me in the documentaion has to do with this:

It discusses traffic moving from A.com to B.com, in either direction (via links). Does this also work if there are never any links between the sites. How would the cookie pass and true up? This parent company has two business lines and wants things to role up if say the user visits Site A on his own accord and buys something. Then a few days later, goes to site B and does the same. Thanks!

[john4math]

I can't speak for Universal GA, but in standard Google Analytics you can use one tracking script across multiple domains with no problem (Google documentation on that).  You can then set up a GA profiles for each of the three domains in your example, and a profile to aggregate them, so you can track how each site is doing on its own, and how all three are doing in aggregate.  You can do this with both subdomains or top-level domains.