Earlier quoted context omitted.
You're sure you're not thinking of Google's Web Accelerator? It wasn't made to prevent phishing, but to speed up browsing, but it caused the problems you describe. http://en.wikipedia.org/wiki/Google_Web_Accelerator
I am sure I am not thinking of GWA. I want to say it was installed somewhat implicitly as part of some virus checking software that people didn't really ask for.
Re: How to detect a page request from Safari 4's Top Sites feature
#11This was AVG antivirus link checker