Cognitive Lode: tips for understanding user behavior online
Cognitive Lode is a nice little resource site by the folks at ribot that aims to educate web-makers about the various behaviors of web-users, “to help you make better products.”
Each study is nicely illustrated, cites additional resources, and generally contains great little nuggets for making better websites.
I definitely learned some new stuff from this site, but others (like Anchoring Bias) may be familiar to some of you. It's also a very nicely designed website if you're looking for inspiration.