A few years ago, during the dot-com boom, Internet backup services were hailed as the next big thing. The idea is simple: using either a conventional backup program such as Retrospect or proprietary software, perform backups as usual, but use secure Internet file serversrather than local or network volumesas the destination. In other words, an Internet backup service is basically a more-sophisticated version of using Apple Backup with your iDisk.
In theory, I like the idea of remote Internet backup. In fact, I used such a service for a whileuntil it went out of business. The problem was that the cost of doing this type of business was out of proportion to the amount of money most consumers could be expected to pay.
Only a handful of Mac-compatible Internet backup services remain, and they are still quite pricey, especially compared to the cost of purchasing your own hard drives. Here are the ones I'm aware of:
All these services are constrained by the uplink bandwidth of your Internet connection, and none can make bootable duplicates.
All these services except Tuloy also compress your data, so you may be able to fit much more on their servers than the amounts listed.
On the plus side, Internet backup services keep your files safely off-site with absolutely no effort on your partand they do so for every backup, not merely on a weekly (or "whenever-I-remember") basis. BackJack, Prolifix, and Datatrieve also encrypt your files (unlike Apple Backup) and make their own redundant, off-site copies of your data (though BackJack charges extra for redundant backups). If, despite my repeated encouragements, you are unable or unwilling to store a set of backup media outside your home or office, an Internet backup service can make that process painless. Even if you do maintain diligent off-site backups, an Internet backup service can provide extra insurance for particularly important files.
These services are no substitute for duplicates. As for archives, unless you have an unusually small home folder, you'll probably find the cost of archiving all your personal files over the Internet prohibitive. But, if you can afford it, an Internet backup service may make a reasonable supplement to conventional duplicates and archives, especially for files you're actively working on. Although these services excel in security and ease of use, you must carefully choose which files to include (or exclude) to avoid incurring extremely large bills.