Rule #1 of Gordon's Laws for Cloud Services:
Is it obvious how to delete your account and all data and services?This rule is always important, but it's critically important for a Cloud backup service. Do you really want to forget or lose control of a complete backup of all your unencrypted data?
CrashPlan failed this test, and others, seven months ago. Back then, during a trial period, I had my backup data on their servers. Their FAQ then didn't describe how to delete it.
I was later told you could delete it by logging in to the CrashPlan account web site, then choosing CrashPlan Central -> Destinations>Online, then selecting "Remove Backup Destination". There was no way to remove an account however.
Today I checked. My account still remains, but now that the trial period ended I don't see an option to remove my data from their servers. Perhaps the data is gone, or maybe if I paid up I'd see it reappear. I wouldn't be surprised by either option.
There's still no way to remove an account from the web site. I also noticed that "My Profile" includes "Receive promotional emails from CrashPlan.com". Hell freezes over the day I opt-in to promotional emails, so that was a sneak play.
CrashPlan is on course to crash landing. When they go into receivership their creditors will own your data. Creditors who need to recover some of their losses.
Update: See comments from CrashPlan. They tell me the data is likely overwritten, and is not recoverable after the promotional period ends. They have no plans at this time for an account removal feature, that requires email (seems a risky practice). Maybe that will change. Comments underscored the importance of client-side encryption.