Why did I write the application ? When I read about Apple's
TimeMachine I thought it's nice tool to have. I searched for
equivalent applications for Linux and I find TimeVault and FlyBack.
I didn't feel very comfortable with TimeVault, especially with it's
time line. FlyBack was almost what I was looking for: I wanted a
Places/Bookmarks column and I wanted snapshots only when something
changed (just to reduce the number of snapshots).

Keep in mind that Back In Time is just a GUI. The real magic is
done by rsync (take snapshots and restore), diff (check if something
changed) and cp (make hard links).

Back In Time acts as a "user mode" backup system. This means that
you can backup/restore only folders you have write access to
(actually you can backup read-only folders, but you can't restore
them).

In order to reduce disk space, it use the following rules:

    * a new snapshot is created only if the last snapshot (if any)
    is different from the current directories state
    * when a new snapshot is created, it use hard-links (if possible)
    for files that are not modified