If every decision 'creates' a new universe, then your birth doesn't depend on the duplicate grandfather in the time travelled universe. Sure time-duplicate you won't live, but that won't cause you to cease to exist.
In a linear universe time travel is paradoxical because you're literally creating a loop in time and any action you take is likely to cause a knot. In a multiverse you're simply rearranging matter to a prior state with the exception of you, it's still a continuous line of time. Time hasn't changed, the matter in the universe has.
I personally believe I'm travelling through time at 1.1second/second and I'm impatiently waiting for everyone to catch up.
See: http://en.wikipedia.org/wiki/Time_dilation
There's also various experiments with atomic clocks proving this on an extremely small scale. Basically, as you move through space, you also distort time.
Way to get my hopes up with the headline crappy science journalism...
It's like saying: Hey! Time Travel is possible. All you really need is a capsule that travels at the speed of light going around an infinitely long cylinder. See? Possible.
