The nine to ten inch netbook seems to be the sweet spot. 12 inches is just too much.
The most recent size shake-out comes to us from the Dell camp. Dell recently withdrew its 12 inch netbook (you can still buy one from the Dell outlet store).
So what's wrong with the foot long netbook?
1. Most likely, it's just too close for comfort to the smaller sized 13 to 14 inch notebooks. Customers don't need the temptation of passing up the bigger ticket notebook for the cheaper netbook.
2. In Dell's case, their 12 inch netbook came bundled with Vista. (file this under "What were they thinking?")
3. Chick's perspective, for what it's worth: a ten inch netbook fits in my purse. A 12 inch netbook would sentence me to a briefcase.
By the way, I've had my 10 inch HP Mini for about a month now. Boy does it get a lot of attention. Everyone asks me about it when they see it. They want to know if it is a good enough substitute for a laptop (Answer: for now, yes. Longterm: no.) They want to know the biggest differences (Answer: no DVD drive). They want to know if its powerful enough (Answer: it's actually got more muscle under the hood than the four year old laptop it has temporarily replaced). They want to know if I take it everywhere (Answer: yes!!!).