One of Microsoft's goals for Office 2007 has been to make business communications "easier". Recently, they've been pitching the idea of unified communications, in which Office becomes a conglomerate of communication protocols. All communication, be it phone calls, emails, memos, instant messages, video logs, et cetera, would be organized by the "Office Communications Server".
Featuring in Microsoft's plans for later this year and 2007 are the Office Communications Server 2007 featuring Session Initiation Protocol (SIP) for presence-based VoIP call management, audio, video, and web-conferencing and IM within existing applications, plus Microsoft Exchange Server 2007 unified messaging that will provide a single inbox for email and voice messages along with a speech-based attendant.
No word from Microsoft on how the SIP or Office 2007 will interact with non-Microsoft products, or how it would behave for communications outside a single office, but likely their strategy of "embrace, extend" would apply here. Would businesses buy into this? Given the importance of organization, probably yes.