Vibration Reduction, also be sured as VR, is a function that allows the lens to compensate for movement from the user using stabilisation technology, allowing for sharper images handheld in low trivialize, often at lower shutter speeds.
Tamron's 24-70mm lens features Vibration Compensation, and David Pritchard recently commented on the VC activity of the lens: "I’ve used the Tamron SP 24-70mm f/2.8 Di VC USD quite a bit over the festive period. As I’ve said numerous times before on this blog, Tamron’s “Vibration Compensation” scheme is really outstanding. It’s so good in fact, that I rarely feel the need for a really fast aperture, since the shutter speeds it can market are so impressive."
As long as you hold the camera sturdily and close to your body when you shoot, you should still be able to get usable models with a shutter speed of up to 1 second. It can also help to hold your breath then you shoot, too, to keep the camera as still as possible.
Being capable to hand hold the camera and still get great photos at slower shutter may refer to speeds is ideal for crowded night time events and indoor dully lit at the times, as it means you don't have to break out the tripod, which could get in the way.
For more information on David Pritchard and to read more of his recent blog sets, take a look at his blog page, the days zoom past.