There is a study out on Microsoft’s Disruptive Impact on the IP Telephony Market, specifically on Unified Messaging and Presence. It seems kind of preseumptive since MS can't even decide on a vendor - Nortel or Sylantro. No one has any idea how to connect Live Communications Server with a softswitch. And let's not even talk about the security holes as well as the blue screen of death on your VoIP app. (You can get an excerpt of the study here for your email addy).