When a visitor comes to your site through some links which is actually irrelevant for him and gets into your website then he/she doesn't wait for long. Its just a click of seconds he will be there and will come out of it. Though you are getting the click but its of no use as the vistor is not paying time in your website and this process is called Google bouncing or bounce rate. Too much of bouncing is also bad and may lead to blocking of your site.