Computerworld has a nice article that points out some reasons that the new netbook craze may be a bad choice for some companies (Small Laptops Pose A Big Security Risk). This is a good warning to companies, especially those larger companies regulated by various federal and ethical rules, that smaller laptops may lose some critical security support.
Of course, the rules for the new mini-laptops should be the same as those for your other laptops: use a label service to track lost ones, use encryption if any customers records are stored there, and be careful accessing your company network using wireless.
The problems come with some of the features left out to keep both the size and price as tiny as possible. Since they're aimed at consumers, most netbooks don't include a hardware chip called TPM for Trusted Platform Module that helps with encryption. Larger and more expensive laptops with TPM support encryption for the disk and for the entire system, often with biometric support like a fingerprint reader. These fully equipped laptops may be larger, but not all that more expensive. HP offers encryption and biometrics on their small business laptops starting at $629.
Larger companies should have in place rules and policies to enforce better user security behavior. My concern is for the smaller companies buying these because they're cheaper and easier to carry. Don't be seduced by the low price and pay a huge penalty for storing critical business information on an easily lost, not well protected little laptop. The money you save with the purchase will be long forgotten when explaining to customers why their account information disappeared along with your netbook.