The dustup between AOL and Microsoft over Instant Messaging (IM) looks familiar. AOL Instant Messenger (AIM) dominates the market now, as Graph 1 shows, but Microsoft's IM service is growing much more rapidly, as Graph 2 shows. And just as in Microsoft's browser war with Netscape, the company's strategy for IM is to include the service in a new release of Windows.

Until now, IM has been primarily in the purview of private individuals, but its inclusion in Windows XP could place the service on nearly every corporate desktop. Moreover, short-text messaging promises to be a useful Web application for cell phone users. But will IM help productivity or just be a new way for employees to waste time? IM everywhere could raise new questions for corporate IT: Should you try to police employees' buddy lists and message content? Should you archive IM sessions? IM itself might be the topic of some lively online chat sessions as companies decide how they can best use this new XP feature.