I have been looking in my error log files for Magento and have noticed that a Google hosted IP often accesses my secret admin URL every day or so. The IPS
I am wondering if this is related to Google Analytics or something like that. Does anyone know about this?
Somehow google found your "secret" admin url. Either you've left link to your admin, or you're using some common word. The only solution is to change "secret" admin url to something "more secret".
Also, do not left your secret admin url into robots.txt, otherwise it's not secret for the attacker.