The main theme from Spark was putting the user (both inside and outside the organization) first. This was felt by all to be a fundamental tenet for the future of IT and architecture by the vast majority of participants, myself included. Interestingly it was something Bill said in his keynote at Mix too.
Dion has done a great article on this on ZDNET with a diagram.
His premise is that if organisations dont step up and put the user first then they will take control. One of the people from a Fortune 100 organisation at Spark commented that blogs and Wiki's were banned in the organisation and all that was happening was that employees were setting up private wiki's for work use outside the organisation.