Kinda Creepy Google Analytics Discovery

Perusing Google Analytics today, I noticed something a little creepy…

If you browse to referring sites, you’re likely to find mail.google.com as a referrer somewhere in your list, as expected.  Take this screenshot from a day last week when we happened to make a big announcement:
Referring Sites - Google Analytics-1
So now, if you’re a Google Apps for Domains customer (as Twilio is), your web UI is located at:
http://mail.google.com/a/your-domain.com
So clicking on mail.google.com, you get a list of referring paths.  But Google reveals some interesting data, that I’m not sure people realize is being revealed:
Referring Site_ - Google Analytics
You get to see all of the companies who’ve been emailing around your links… including entry pages, # of uniques, etc.  Pretty interesting intelligence, especially when you find competitors in the list :)