Why would I use this to backup my address book, stickies, ical, safari, keychain and all those other items that already sych with mobileme? It is already on mobileme, why would I backup up again to it?
Because backing up is all ABOUT redundancy
But seriously speaking, there are major advantages to backing up this way. Since first becoming a mobileme member in 2003 (well... it was dot mac then) I've had more than 1 instance where my address book has become corrupted. The problem is, this corruption (whether it started on my mac, my iDisk, or somewhere in between) was synchronized, so that ALL sources of my data were corrupted. In that case, something like Time Machine or Backup.app will allow you to revert to a copy of your address book from a few days ago, before the data got corrupted.
If you're already using Time Machine, then just look at backup as an automated way to get your data offsite.
No, it's not a good enough application (nor is there enough space on my iDisk) to back up everything that I'd like to. However, I do have my most important documents backed up (in addition to the personal settings like bookmarks, keychain, address book, etc.)
To back up your documents without totally filling up your iDisk, I'd recommend opening up your Documents folder in the Finder and sorting by Size, and seeing which folders are enormous. Go to Backup and make a backup plan for your Documents folder, excluding the specific folders/files that are enormous.
Unfortunately, you'll still have the keep an eye on your Documents folder for those times in the future when you add MORE huge files/folders to it, but for the most part, this is a workable, and LARGELY "set it and forget it" solution.
