[tacticalogic]

iCloud is a syncing service. It makes sure that you have the same files, documents, music, and apps on all your devices: Macs, iPads, iPhones, iPod touches. For example, if you buy a song on your iPod, it gets downloaded automatically onto your iPhone, iPad, and iTunes on your Mac when you are online.

Does it also mean that if any one of those devices gets lost/stolen and hacked, whoever has it has access to all of your data?

[ReignOfError]

iCloud is a syncing service. It makes sure that you have the same files, documents, music, and apps on all your devices: Macs, iPads, iPhones, iPod touches. For example, if you buy a song on your iPod, it gets downloaded automatically onto your iPhone, iPad, and iTunes on your Mac when you are online.

Does it also mean that if any one of those devices gets lost/stolen and hacked, whoever has it has access to all of your data?

If by "hacked" you mean that someone figures out your passcode or gets around security, or you have it unlocked to begin with, then yes. Same as if your data is resident on the device. Anything that lets you get to your data could potentially let someone else get to your data.

If your device is lost or stolen, you can lock it down and wipe it remotely.