Accountability in 'the cloud'

Ignoring the irritating marketing term of 'the cloud', I'm all for putting stuff online. I'm a big user of dropbox, which lets me store files in a datacentre somewhere. I use google docs from time to time, which lets me access a file from anywhere I happen to be. I use Evernote on my laptop, phone and work desktop. It's all good.

But... what about responsibility for that data?