When to not do cross-domain tracking
Cross-domain tracking is great. But just because you can do something doesn’t always mean you should. This goes for cross-domain tracking as well. Sometimes tracking two domains as separate sites instead of together, may be the right approach.
While there is no hard-and-fast way to make this decision (that I know of), here are a couple things to consider.
*Can visitors be commonly expected to cross from one domain to another to accomplish your goals? Their goals?
*Do the domains serve different audiences?
Imagine, for example, pbs.org and pbskids.org. These two sites (usually) serve very different audiences. And someone would not normally be required to cross from one domain to the other in order to accomplish their goal. This situation is probably best served by tracking them as different sites without any cross-domain tracking.
Another example is a company such as Perillo Tours that sells vacation tours. There is one domain that is the consumer facing site (perillotours.com)– you and I can buy a tour on this domain. The other domain is for travel agents to purchase tours for their customers (perilloagents.com). Both sites are virtually identical (they provide almost the exact same functionality, after all). Although you can move between sites, the two domains are serving different audiences and the visitors would not need to cross domains in order to accomplish goals. This is another example of when you’d not want to use cross domain tracking.
Again, these are just a couple examples and some things to think about when trying to decide if you want to implement cross-domain tracking. It may not apply to most of you, but for those in a situation like this, I hope it helps get you thinking about how to implement GA for your domains.