Yahoo didn’t just release their Yahoo! Design Pattern Library today, they also have the ajax code for it available for free. Yes, you can use this Yahoo-tested, mature code in your own commercial projects.
What’s in it for Yahoo!? They are releasing it under a BSD open source license, but I don’t think their main motivation is to get outside programmers to help improve the code by open sourcing it. I think their motivation is to become leaders in setting new UI standards for the web.
Let me explain. Web UI’s are becoming pretty rich pretty fast these days. However, there is no clear leader that sets standards. If Yahoo can make their own standards become adopted by many web properties, it inforces the familiarity users have with the Yahoo! UI standards. If Yahoo! uses a slider widget, and that works the same on a bunch of other websites too, the slider becomes a standard for users, something they can rely on. And all Yahoo!’s properties become standards too.
I like this strategy, it’s clever. It’s saying: follow us in UI design, we’re the leaders. And giving people the tools to easily follow them (how hard will it be to convince a manager to use drag&drop if it is “good enough for Yahoo to use”?). This way, Yahoo’s UI becomes a standard rich web UI.
Google, meanwhile, is showing how bad they really are at UI. The new chat implementation in Gmail is really, really bad, to the point of being unusable.