Why Phishing Works...
If you haven't read "Why Phishing Works" (850 kb PDF) - written by Rachna Dhamija, J. D. Tygar, and Marti Hearst - stop what you're doing now and go get it...
https://people.deas.harvard.edu/~rachna/papers/why_phishing_works.pdf
Very frustrating... ;-)
-Urs