I just noticed them today. You can't feel them unless you run a bare nail across them. They're along the black plastic portion of the 15" Macbook pro (late 2008 model) at the base of the screen. The computer is less than a year old and I rarely ever actually move the notebook. It spends most of its time on a stand at a desk in my office. Other than that it goes out once ever few weeks to talk to clients. I don't know what could've caused the cracks. I'm thinking it could be heat related. I just looked into it today and noticed that my cpu was sitting around 200F. I installed a FanControl which has help pretty significantly, but it doesn't seem to ever go away. Since I'm sure that the cracks are not caused by misuse, it leads me to believe it might be something wrong with the computer. The smooth operation of this machine is crucial so if there's something wrong, I'd like to try and catch it early. Any advice?