The Async Tracking code in Google Analytics looks like this:

var _gaq = _gaq || []; 

_gaq.push(['_setAccount', 'UA-XXXXX-X']); 

_gaq.push(['_trackPageview']); 



(function() { 

  var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; 

  ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; 

  var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); 

})(); 

About The first line:

var _gaq = _gaq || []; 

I think it ensures that if _gaq is already defined we should use it otherwise we should an array.

Can anybody explain what this is for?

Also, does it matter if _gaq gets renamed? In other words, does Google Analytics rely on a global object named _gaq?