Read/WriteWeb has an interesting post announcing the official release of Yahoo! Messenger with Voice and info on plug-ins.
Third-party developers can create plug-ins (aka widgets) for the platform. This has already proven to be very popular – since opening up the plug-in platform on June 20, third party and Yahoo! developers have developed 180 plug-ins worldwide.
The most popular plug-ins for Y! Messenger are currently utilities like Pando (a way to share large files and folders), YEmote (emoticons), an eCards widget, an iTunes “remote” and a drawing/photo tool.
I don’t know how many plug-ins are out for Windows Live Messenger, but Yahoo! currently sounds like it’s been more successful in this area.
Microsoft this week launched Windows Live Gallery, a one-stop shop to personalize your Windows Live experience. Live Gallery helps you find all the cool & useful Gadgets, Toolbar custom buttons, Messenger Bots and much more.
Since Windows Live Messenger plug-ins functionality is still in beta and is not turned on by default, there aren’t any available on there. For the same reason, I’m not surprised there aren’t as many plug-ins for Windows Live Messenger as there are for Yahoo! Messenger.