As I already mentioned yesterday .. Microsoft was going to announce something big at Convergence . As I'm not in the States myself, I don't know the details of it, but it seems that it's quite good explained in this news article: Microsoft Unveils Plans To Adapt Its ERP Applications For Cloud Computing.
Because of the fact that AX, GP, NAV and SL are al quite different technologies .. it seems that they have to work out the specific details .. , but Kirill (Tatarinov) said: "For now we thought that it was appropriate for use to articulate the vision and the roadmap, the directional statement". So we know they're heading to the cloud .. or like Steve Ballmer says: "We're all in" :-).
The next major releases of Dynamics AX, GP, NAV and SL will be developed to run on Windows Azure, Microsoft's cloud development platform that's been available for a year, Tatarinov said, beginning with the next version of Dynamics NAV that's due in 2012. The applications will support multi-tenancy, he said.
I translate that in: NAV 7 will run on Azure in 2012.. . [:-)] And we all know Kirill .. if he says it's gonna be in the cloud .. then it's gonna be in the cloud!
This was confirmed later by Dan Brown during the NAV keynote: NAV 7 on Windows Azure, SQL Azure and connecting to Office 365, release date H1 2012