Things are heating up in competition for instant messaging market share. Monday saw the release of Microsoft's Windows Live Messenger, and on the same day Yahoo delivered an upgraded version of its IM client, while also providing tools to third party developers to write "plug-ins," or add-on tools, for the software. Clearly, Yahoo hopes that opening up its IM tool will help it stay ahead in the IM arms race.

Elinor Mills at ZDNet reports that the web portal and its partners have already released upwards of 20 plug-ins for the client that allow users to monitor eBay auctions, share calendars, and listen to music while chatting, among other things. With messeging tools taking on more functionality, notably adding voice messaging (or VoIP) capability, the IM client may now have usurped the web browser as the Internet's most contested turf. For some, however, piling all of these new features into chat software is too much. "I don't know about you, but I'd prefer my core Web services in my Web browser," writes John Paczkowski at Good Morning Silicon Valley. "Adding them to an instant messaging client just seems to be needlessly mucking things up."