It’s convenient to have an entire bootable Linux distribution on a USB thumbdrive. If you don’t want to carry around an optical disk (or if you have a computer without an optical drive), you have a handy, bootable drive ready to either boot and do some quick triage, or install on to any computer. There are several ways to create a bootable Linux USB key, but the easiest way is with UNetbootin, an open source utility available for both Windows and Linux. It can automatically download dozens of Linux distributions, but these choices might not be the right ones for a netbook.
Fortunately, UNetbootin can use any manually-downloaded Linux distribution. For a netbook-friendly thumbdrive, we'll set ours up to use Ubuntu Netbook Remix, which is, unsurprisingly, a simple Ubuntu variant for netbooks. Download the .iso from Ubuntu’s site, open UNetbootin, select “Disk Image Option,” and load the freshly downloaded .iso file. Plug in at least a 1GB USB key you don’t mind wiping (the process erases all data on the drive). Make sure the program says “USB drive” and has the right drive letter highlighted. Now just click okay and watch the magic. Note: When it’s done, you probably should NOT click “Reboot” unless you want to load Linux on the computer you’re currently using.