<Disclaimer>This is personal notes of what I retained during the session. This can be incomplete, partially right or wrong. It is just  part of the notes I took and what retained my attention. Nothing prevents the user to get more information on their favorite web site.</Disclaimer>

Basically, S+S is about externalizing services like we have done with the power. Instead of having every home producing power, we have now plants that are producting it, and home connecting to the grid to get what they need. It is more or less the same with the Cloud. Someone is hosting the resources for you, no need to care about scalability, failover and so on, letting you concentrate on the development of your application. This allows also to publish your own services into the Cloud, making them available for others. A parallel can be done with the transport systems :
A car corresponds to the on-premises infrastructure. But it has a maintenance cost and needs to be fixed or patched.
Car renting is better and is like hosting.
On its side, the train is equivalent to the Cloud. No need to care about the maintenance at all, but, the downside is that you can not change the schedule or where it goes.
So, when looking for the Cloud, it is looking for availability, scaling, but you have no control on it. It also means that the Cloud is not the silver bullet and is not for everything.
To manage the identity, the .NET Services (one of the Cloud services) relies on external authorities. The enterprise defines the identities and roles and build a trust relationship with an external authority that will be trust by the Cloud. It means also that .NET Services needs to support several technologies.
It leads to, at least, two challenges : to focus on the use of SOA, and on resources decentralization.
To support the ID management, Cloud is using tools such as claims, tokens and Security Token Services.
Finally, to control the identities on .NET Services, there is a MMC to manage them.