google analytics - multiple trackers on one page (cookie conflict)

Question

I'm writing a web application that's supposed to be embedded in other people's websites (kind of a widget). I'm using Google Analytics to track all the people that visit all instances of my script on the embedding websites. The problem is that I don't know how to use it so that it doesn't interfere with those websites' own Google Analytics accounts. I'm storing the tracker variable in a namespace, so I thought that should do it, but I haven't realized that GA stores its settings in cookies (__utma, __utmz etc.), and those cookies are used by both trackers, if there are two of them on the same page... So for example if I use _setVar to store some kind of user-defined variable in Google Analytics, and the embedding site does the same, we overwrite each other's values...

Of course it would be easiest if Google provided a way to change the name of the cookies to a custom one, but I can't find any way to do it. I thought about using cookie domain or path to force a separate cookie, but this doesn't work, because if I set domain or path to something other than the real domain/path, then the cookie is not readable for the page after reload...

Does anyone know a way to have two trackers on one page and make them use separate cookies so that they don't overwrite each other's settings?

Or, if that's completely impossible - is there any other analytics service with similar functionality as GA in which this is possible? (it would have to have advanced features like event and campaign tracking...)

Answer 1

This person is having the same problem on the Google Analytics help fourm. I'd suggest taking a look at the thread. But regularly GA doesn't support multiple trackers.

I like Clicky myself, but it costs money.

Answer 2

Don't have to use different cookie names as Google Analytics happily works with multiple trackers on the same page. See answers for question Google Analytics - Multiple Trackers for Several Accounts?.

Update

It turns out that using multiple trackers is a working method but has some pitfalls. One of those, that is, you cannot apply different user segmentation for each of them. John Henson demonstrates a workaround that coerces GA to use different cookies, may be you should check it.

Answer 3

According to the documentation listed by Török, it seems the correct answer is to use _setCookiePath. This causes each tracker to use completely different cookies.

Example code from website:

<script type=”text/javascript”>
    var pageTracker = _gat._getTracker(”UA-11111-1″);

    pageTracker._setDomainName(’domain.com’);

    pageTracker._setCookiePath(’/subdirectory/’);
    pageTracker._trackPageview();

    var otherTracker = _gat._getTracker(”UA-22222-1″);
    otherTracker._setDomainName(’domain.com’);
    otherTracker._trackPageview();
</script>

When you link from one domain to another, every link that posts to the other domain has to look like this:

<a href="pageTracker._linkByPost('otherdomain.com/petStoreCart/legalTerms.php');"

This will add Google Analytics specific query string values that will be used by the above script to set the cookie (source).

Answer 4

var otherTracker = _gat._getTracker(”UA-22222-1″);
otherTracker._setDomainName(’domain.com’);
otherTracker._trackPageview();

Answer 5

Now made easy with the new asynchronous tracking code. :)

http://code.google.com/apis/analytics/docs/tracking/asyncUsageGuide.html#MultipleTrackers