The scourge of web analytics
I could never understand why any ecommerce company would use GA.  They are collecting your user's data for ad targeting.  Well, guess what?  They target ads to your users for competitor's products.You browse a site that has GA on it looking to buy a bike, then that user get hit with bike ads on other sites that host Google ads.  Almost every site owner I've spoken to about this issue was unaware of it.Server side analytics prevents this, or use an analytics package that has no advertising business.