There's a good article by Clive Thomson called The Netbook Effect in the latest issue of Wired Magazine that's worth a read. In it Thomson explains the netbook phenomenon:
When Asustek launched the Eee PC in fall 2007, it sold out the entire 350,000-unit inventory in a few months... Soon the major PC brands—Dell, HP, Lenovo—were scrambling to catch up; by fall 2008, nearly every US computermaker had rushed a teensy $400 netbook to market.
I just picked up a Dell Mini 9 (pictured at right on top of my MacBook Pro 15-inch) and have to admit to being impressed. Sure, it's tiny, but it's supposed to be tiny. It's perfect to use on a plane or in a coffee shop which is exactly the purpose of this type of computer.
I picked up the 16GB (flash) configuration with Wi-Fi, Bluetooth, Webcam, XP and 2GB of RAM for just over $400, but they start as low as $249. Buying XP was probably a waste of money (picking Ubuntu saves you $65) as I'm going to install OS X on it soon.
And I'm not the only one. My co-host and engineer on the PowerPage podcast Rob Parker was recently tempted by an Acer Aspire One he was configuring for a family member and just about every journalist and writer either has one or wants one.
Apple said that it doesn't want to make a computer under $500 dollars because it would be "junk," but I think that they're foolish for ignoring this white hot section of the market.
What do you think? Are netbooks just another trend or are they the real deal?