Parker Harris gave a presentation a couple of days ago on the new Service Cloud 2 and made a really interesting statement concerning downtime as reported by VentureBeat:
Now, Harris said Salesforce is testing a program that would give customers access to their applications even when Salesforce is upgrading its service. Initially, you’d only be able to view the applications, not interact with or update them, but even that is “really, really hard,” Harris said.
This would be huge for companies that don't like to be cut off from their data (e.g., everyone). Companies that utilize Salesforce.com for their call centers will be primarily affected. When scheduled downtimes affect their operations they typically have contingency plans that may involve dumping their data to another application for read access and then entering new data into spreadsheets which later require import.
If Salesforce.com can put this into place it will allow CIOs to mark off another item (24/7 data access) from their cloud-adoption requirements checklist.