[Disclaimer: I don’t have a T-Mobile account nor a Sidekick] The information is stored on your phone, too. But you’re supposed to be able to recover information from their servers. Indeed, T-Moble even implies this saying: …we must now inform you that personal information stored on your device – such as contacts, calendar entries, to-do lists or photos – that is no longer on your Sidekick almost certainly has been lost as a result of a server failure at Microsoft/Danger. My question would be to ask which copy is the Master and which one is used to resolve conflict? On my Blackberry, this is configurable to a degree. I would hazard to guess that if your Sidekick is config’d to rely on the server copy as the Single Version of Truth, then well, you might have a very significant problem. — What is strange is that Microsoft planned so poorly when they attempted to upgrade their SAN storage. There are a myriad of ways to ensure this kind of problem does not happen. And apparently, Microsoft didn’t care to implement any of them. Now there’s a company that takes your money and gives you very little in value in return.