My 5mo. old white Macbook has a very small, nearly imperceptible crack right below the trackpad. It goes from the bottom of the trackpad to the small crevice where you pull it to open it (if that made sense). It's maybe 1/6 of an inch long and is hairline thin. I was wondering if this is anything that is going to affect my computer in the future? It's so small that I think with careful handling it won't get any worse. Is this a common problem on other Macs? I'm hesitant to take it in again because I just got the whole optical drive replaced and don't feel like dealing with Apple store employees for a while... Thanks!