Camera shutters are tested/rated for a certain amount of clicks. My camera for example, is tested for 150k clicks, and as of today had done about 12k. So it gives you an idea of how used the camera really is. However, this doesn't mean that the camera will suddenly stop working after 150k clicks, its just that this is what it has been tested to do. As an example, I have a friend whos Nikon D700 that has just done its 325000th click, and its still going strong.
I think sometimes, people can place too much importance on shutter count.
Hope that helps.