Defining the Netbook
They’re all wrong. Everyone that’s perplexed as to whether or not the new Dell Mini Inspiron 12 is a netbook or not have fundamentally misunderstood what defines a Netbook, while for once Dell seems to have a complete understanding of the concept. What impresses me about Dell is the fact that they’ve done this better than any of the other manufacturers that have jumped onto this bandwagon; and seeing as only Apple and Sony not having joined in on the fun, that’s basically every manufacturer of a computers out there.
A Netbook encompasses a range of concepts for a computer to be classified in this manner:
Size and Weight
This is the "acid test". Is the netbook light? Can you imagine carrying it around all day? Is it around 1kg? if it's much heavier than 1kg, is it slightly larger and therefore distributes the weight more? Remember the Macbook Air is heavier than all the netbooks but due to the weight distribution it feels lighter. 12inch is the absolute maximum you can go up to, 9inch is the minimum that you can use without it being bloody annoying. 7inch models are basically too small for anything apart from checking some emails.
Speed and Power
The ultimate specifications of the netbooks is pretty irrelevant. It seems that Intel had brought netbook.com but now it just redirects you to the Intel website. i guess it's because they realised hopefully that a netbook isn't a netbook because it's got an Atom processor. The fact that most of them do again is irrelevant. It's a nacesent category. The other players haven't jumped into the ring. They're still waiting to see if this is all going to fade away. The power associated with a netbook is meant to provide you with the power that is needed to perform the tasks that one would expect from a netbook. I wouldn't be wanting to render any images, nor do any serious graphic work, nor watch a movie. I'm using this for web surfing, for emailing, for having a look at a couple of pdfs and doing web related stuff. Anything else is noise.
The processor should hopefully reduce the power consumption to a minimum and allows the software to load quickly. I am still waiting for the software to be integrated so much that the waiting is non existant, however that will probably come in time.
Bloat and Affordability
The major concept behind a netbook that is common however to all is the fact that a netbook gets rid of bloat and unwanted items. It strips the computer down to it's bare. No optical drive is a critical one, because that goes against the concept. If a computer has an optical drive, it's not a netbook. Storage is really down to preference i guess. In reality you won't need to have major storage. 20Gigs should be more than enough. The only reason you'd have more maybe is for all your music if you want to listen while doing your other things - but most of us have ipods right?
Which finally brings me to affordability. This isn't a primary machine. This is a pretty fundamental concept here. You won't be using this as your work horse, but rather as your secondary throwaway machine. Therefore you don't want to be spending too much on this because you can't really justify the extremely steep expense. There is a cut off on general price, which is why the Air can't really classify as a netbook, because that machine was built to tackle more than just web based activities.
KISS

So why do I think that Dell have understood the market better than Asus, the category generators? The answer is down to simplicity. If you try and get a netbook from Asus, they've absolutely swamped the market with no less than 12 different models (and that doesn't take the XP and Linux variations).
In stark contrast Dell have released their Mini 9 (with an Ubuntu or XP variant) and now the Mini 12. Don't even get me started on the Swarovski 'enhanced' S101 netbook. The industrial design of netbooks should have one and only mantra, KISS - Keep It Simple Stupid.
Only What You Need
It's the form factor relating to what you are ultimately going to use this secondary machine for. Because based on the above, you're not going to be using it for anything but sitting in the lounge (or the garden) or about town to do simple stuff with a machine that meets your basic needs, rather than all of your needs, and crucially not more.