Anyone that’s used Google Analytics to track cross-domain requests has probably run up against the fact that Analytics adds some really ugly GET variables to the end of your URLs when you click on links. Not only are they ugly, but they also can stop things like WP Super Cache from caching your pages. We also found that the query string appended by Google Analytics was causing server errors when appended to the URLs of some of our hosted apps.
There is a little-publicized feature in Analytics, though, that lets you change the query string into a hash string. Therefore, instead of having some long, ugly string that can mess things up (and, to be honest, long, confusing query strings can sometimes scare users); you get a long, ugly hash appended to the URL, instead (which has no effect on the way the page is rendered, and, therefore, doesn’t mess up nearly as many things).