Marc Andreessen, 2007: "You have to provide a runtime environment that can execute arbitrary third-party application code. You have to build a system for accepting and managing that code. You have to build integrated development tools into your interface to let people develop that code. You have to provide an integrated database environment suitable for applications to store and process their data. You have to deal with security in many different ways to prevent applications from stepping on one another or on your system -- for example, sandboxing. You have to anticipate the consequences an application succeeding and needing to be automatically scaled. And you have to build an automated system underneath all that to provide the servers, storage, and networking capabilities required to actually run all of the third-party applications."
Gina Bianchini, 2008: "Third party widgets and applications are entirely separate from Ning. We cannot be responsible for them nor guarantee that they will continue to abide by our Terms and therefore be available. Moreover, our policy not to discuss the details of violations publicly limits not only what we can say after an event, but the advanced warning that we can provide before it.
We would have loved to provide ample warning to Network Creators about this decision. The difficulty is that I'm not sure there would have been a way for us to do so that didn't violate the privacy of parties involved."
Steve Loughran said a while back that you can't just treat the cloud as a cloud because you have to know where your data is, for non-technical reasons. So it looks like this nascent industry has some policy issues to work out, but I still find Andreessen's "level 3" vision inspirational:
"I believe that in the long run, all credible large-scale Internet companies will provide Level 3 platforms. Those that don't won't be competitive with those that do, because those that do will give their users the ability to so easily customize and program as to unleash supernovas of creativity."