Christian Belady of Microsoft shared some preliminary details of their new modular data center concept several weeks ago, and now Kevin Timmons, Microsoft's general manager of data center services has made the plans public at DataCenterDynamics in New York. View the slide deck, and be sure to run the embedded video.
The container data center concept is not new, and Microsoft operates some of the largest data centers in the world that use containers (manufactured by Dell). I would not call ITPAC - "IT Pre-Assembled Components" - a container though; it's better thought of as a site-built modular unit.
Microsoft touts several advantages for ITPAC, including low construction costs using recyclable materials, and the ability to add capacity essentially "just in time", in whatever increments are needed.
(By the way, this will put pressure on the utilities that serve Microsoft data centers in terms of providing power capacity. Do you build multi-MW distribution from the jump, or try to match the data center load increments as they're added?)
The real excitement for me is the claim of very low PUE: 1.15 to 1.19, depending on local environmental conditions. Because ITPAC is really an air handler with a direct/indirect evaporative cooling element, there is no need for chilled water or mechanical cooling whatsoever. Hook the unit up to power, data, and a simple water line to feed the evaporative cooling element, and you're done.