What is Anti Shake in a digital camera?

so I'm buying a camera and it has anti shake ?? can someone please explain to me what that is and what it does please before i buy this camera? :) Thanks helps alot :) http://www.amazon.co.uk/Vivitar-Vivicam-Megapixel-Digital-Camera/dp/B0049NGBFW/ref=sr_1_1?s=electronics&ie=UTF8&qid=1309464338&sr=1-1 {The camera I Want To Buy}. :D