Text flickers while scrolling ?

Hello,

When I am scrolling on my Macbook Pro (bought Fall 2009) I often experience that text and horizontal lines flickers. For example it is quite visible on Apple's store http://store.apple.com/us - primarily when I am not scrolling so fast.

Is this supposed to be like this or should I contact Apple about it ?

I am not sure if it has been there from the beginning, but lately I have noticed it and started to think about if something could be wrong.