Netbooks are a relative newcomer to the world of portable computers. They sit comfortably at the opposite end of the spectrum from the "desktop replacement" notebooks, those laptops with big screens, beefy specs and full-sized keyboards. Netbooks sacrifice optical drives (CD/DVD drives) and have generally modest hardware specifications, smaller screen sizes and shrunken keyboards. They also tend toward smaller hard drive sizes oftentimes much, much smaller. What you get in return is a small PC that is truly ultra-portable though, weighing in at less than 2 lbs in some cases. In other words, a netbook is an ideal travel companion.