Personally, when I think Yahoo! I think "Bubble-Yum Bubble Gum". It's good in an AOL kind of way. A useful portal for general populace, but it's always too icky, overloaded, and feature-poor for my tastes. This is in-spite of the fact that the president and CEO is a fellow Alum.
However, Yahoo! has really suprised me and released some very cool developer resources.
- Design Patterns - numerous UI concepts, descriptions, and implementations for various application tasks
- User Interface Library - collection of JS, DHTML, site elements for websites
- Yahoo! User Interface Blog (rss)
- Browser grading chart for following standards
- via vanderwal.net