For a while there it looked like 2009 would be remembered as the Year of the Dead Celebrity. But Michael, Farrah, Walter, Ed, and all the rest may have to move over. This is rapidly becoming the Year the Data Died.

Exhibit A, of course, is the T-Mobile Sidekick Debacle, with Microsoft subsidiary Danger in the key role as the clueless initiator of disaster. ("Gee, I wonder what pushing this button will do...") They screwed the pooch in a half-dozen ways, starting with a weeklong outage that went completely unacknowledged until Sidekick users started kicking up a fuss in forums and the media picked up on it.

[ Also on InfoWorld: "Microsoft screwup puts T-Mobile users in Danger" | Stay up to date on Robert X. Cringely's musings and observations with InfoWorld's Notes from the Underground newsletter. ]

Then it took them another few days to warn users to not reboot their Sidekicks (which is the first thing you're told to do when something isn't working right) because that would wipe out their data. Then the announcement last weekend the data was lost forever, followed by another announcement that maybe some of the data wouldn't be lost forever.

T-Mobile -- which appears to be mostly blameless in this scenario, yet is getting a ton of heat for it -- reacted by offering free data service for October, a $100 credit, and a halt to new Sidekick sales, and reportedly is letting people out of their contracts without penalty. No matter; its reputation is still toast.

Microsoft/Danger have yet to explain what happened, but speculation is rampant. There can only be two reasons for this kind of bungling: One is a Keystone Kops level of ineptitude by a lot of different people at Danger; the other is sabotage. And given the rancor following Microsoft's mostly unreported layoffs of key people at Danger last May, the sabotage theory is starting to gain some traction. All you need is one disgruntled employee with some technical savvy to leave a software time bomb behind.

Exhibit B: The Apple Snow Leopard upgrade. Amazingly, some unlucky Mac users who access their systems using the "guest" login get a special treat: Snow Leopard wipes out their personal data. (As the saying goes, that's no way to treat a guest.) Apple has acknowledged the problem, says only a small number of users have been affected, and is working on a fix. If not for Microsoft's complete bungling of the Sidekick situation, Apple would be in the hot seat this week.

Exhibit C: For the past 10 days or so, Facebook has been grappling with a data loss problem of its own, which it finally acknowledged yesterday. About 0.05 percent of its users -- roughly 150,000 if Facebook's subscription numbers are to be believed -- had their personal profiles flushed down the technology toilet.

I've been in touch with a well-connected Cringester who lost close to 5,000 contacts in Facebook and was in the process of slowing rebuilding her friends list, one FBer at a time, when her account was finally restored. She received an e-mail that attributed the disappearing act to "an extended technical issue." Hmm, ya think so?

However, parties close to sources inside Facebook tell me the service was hacked. (If I can confirm that, or learn more about the actual cause, I'll let you know.)

If that's true, it wouldn't be the first time it's happened -- though it would be the first time so many user profiles were totally scotched. Still, regardless of the cause, it's troubling, especially because I don't know of any way to back that stuff up.

Wait, we're not done yet. If you live in Sweden, for a brief period you were transported back to the pre-Internet era when a software script updating DNS records left out the dot in the ".se" country-level domain -- effectively making nearly a million Swedish sites invisible to the InterWebs.

No data was lost, as far as I know. But think about it. The entire Web can be taken down for want of a single period. Does that make you nervous? It should.

The lessons du jour: Back up early, back up often, and don't rely entirely on something that might not be there when you need it most.

Has a service provider ever lost your precious data? If so, what did you do about it? Post your stories below or e-mail me: cringe@infoworld.com.

This story, "2009: The year your data died," was originally published at InfoWorld.com. Follow the latest developments in security at InfoWorld.com.