What’s a Netbook? Well I would start with the Wikipedia definition: A netbook is a light-weight, economical, energy-efficient laptop that is designed for wireless communication and Internet access.Suitable for web browsing, email, and general purpose applications, netbooks are targeted increasingly at cloud computing users who rely on servers and require a less powerful client computer.
There is a good article on Netbooks in a Wired Magazine blog. You can read it by clicking here.
I would define Netbook as a sub $500 laptop using the new Intel Atom Processor with a less than 14inch screen and typically no optical drive (CDROM).
Why a netbook? If you use your computer to mainly access the internet and send email then you clearly do not need to spend a thousand dollars. That's what netbooks were designed to do: use the internet and send email. These low cost and super lightweight computers will do everything the typical Realtor needs to do.