According to this article at GottaBeMobile, Asus is phasing out the 8.9" screens on their netbooks.

I rather like my little 8.9" netbook, because I can stuff it in my coat pocket (I have big pockets), and it's super handy. However, typing on it is a bit of a chore, and the 10" format is probably going to be what's standardized on due to the much better overall usability.