I'm adding an "m" subdomain to agilitycourses.com to provide a better mobile browsing experience. I'm using the referrer string in Django middleware (currently using minidetector) to detect whether the client is mobile and redirect them to the mobile site. Since it is likely that some folks will/won't get appropriately redirected I was looking for an easy way for them to tell me when they were incorrectly redirected. I'd need to know their referer string.
A little googling turned up a nice one purpose website: www.whatismyreferrer.com/