Let's not forget that Carbonite runs only under Windows (incl. Vista). A solution for the Mac was due "mid-2008", but still hasn't arrived, and there's no sign that it'll ever work for Linux or (non-Apple) BSD users.

Linux and BSD/MacOS users can use a different solution, using Amazon's S3 storage mounted as a filesystem using "s3fs", plus standard backup tools like BackupPC.

Carbonite is high on my list of "never do business with" outfits. Their client software was pretty lame, no diagnostic/debugging tools of any sort and very limited control. The automatic file monitoring did not work on folder-mounted NTFS volumes and it took me two weeks of frustrating communication with their customer service to realize that they are useless. I had to send an angry e-mail to the CEO to get my money back. That was a year ago though, might be different now, i.e. they might be ignoring CEO's e-mails now :-)