Yahoo! has an (semi-) official User Interface Blog that discusses their developer library, explains their design tricks and helps folks to understand how to use their APIs to the fullest. It's a nifty idea for a site and the images that are explained in the blog posts make it good reading for UI tips and tricks. An example post is below:

Problem Summary

A user wants to quickly leave their opinion on an object, with minimal interruption to any other task flow they are involved in...One excellent design principle to follow is to allow the user to leave a light footprint. This means encouraging light-weight actions for engagement by providing invitations. Instead of the user having to go through several steps to rate a movie or a news article, invite them to simply click to rate. The Rating an Object pattern is an excellent example of this principle.