"Centralization is in many ways the worst part. It's the core of the cloud computing model, and anything that takes down the centralized service–network failures, massive malware hit, denial-of-service attack, and so forth–affects everyone who uses that service. When the documents and the tools both live in the cloud, there's no way for someone to continue working in this failure state. If users don't (or can't) have their own personal backups, and don't (or can't) have other tools with which to access their backups, they're stuck.
"The cloud computing model may be a wonderful system when it works, but it's a nightmare when it fails. And the more people who come to depend upon it, the bigger the nightmare."