Yahoo! Messenger Plugin SDK

When I was in Yahoo!, I heard about this new plugin architecture in Yahoo! Messenger. I was very excited because I could extend the capabilities of Yahoo! Messenger with my current skills set (ActionScript, HTML, JavaScript, C++). Now this is public, I can talk about it.
You can download the latest beta of Yahoo! Messenger and get the Yahoo! Messenger Plugin SDK (which contains a sdk documentation and one example plugin).
Justin has also blogged about it. I am sure, we would soon see some cool plugins. Yeah, I also have my own ideas which I would hopefully able to do in my free time.
Meanwhile, check out plugin-gallery for some cool plugins.