Only if you do an incremental backup each time.
As I understand it, that's the way Carbonite (and I think the other
online backup services, too) works.
How paranoid are you,
and can you afford to lose the safety of having a known good copy of a
file that hasn't been corrupted by this week's malware?
I am extremely careful about what I do and what anti-malware programs
I run. I've been running personal computers since 1987 and have never
been infected with any form of malware.
That's not to say I'm immune form malware, of course. None of us is.
But my risk is considerably lower than the average person's
And I were to use a service like Carbonite (I haven't decided yet) I
wouldn't rely on it completely. I also have several external hds, and
would continue to back up to them periodically (but not every day).
Moreover my most critical data is my Quicken file, and I backup that
up to thumb drives (alternating between two thumb drives) every three