Microsoft Unveils Exchange 2010 With Public Beta

Microsoft releases Exchange 2010 for public beta today. From the press release:

A public beta of the server is available for download starting today at http://www.microsoft.com/exchange/2010...Exchange Server 2010 will become available in the second half of 2009. Microsoft Office 2010 and related products will enter technical preview in the third quarter of 2009 and become available in the first half of 2010.

Information Week provides some more details on the release, including some hints at Outlook Web Access upgrades:

Outlook Web Access -- and likely the other versions of Outlook, though Microsoft wouldn't confirm -- will include an instant messaging client compatible with Microsoft Office Communications Server and Live Messenger. Microsoft will offer APIs to allow other third-party IM clients to work in Outlook Web Access.

To me the big news is the integrated e-mail archiving, which finally gets Microsoft into the e-mail archiving market. Some are concerned about it being a disruption to the existing e-mail archiving vendors, however I think it's about time that there is more seamless integration of archiving into messaging platforms with centralized controls. I'm still unsure how it's implemented, which is all the difference if this is disruptive or not. My specific questions include where are the archives stored, what are the archive file formats, do the archives support stubbing/re-stubbing or single instance store, and does the archive system provide record disposition or tiered storage management?