When I see or hear about a new netbook in the market, the very first question that pops into my head is "How's the battery?". This is then followed by "What is its processor?" and other questions about the netbook.
The reason why I ask first about the battery is that most netbooks today bear the same specifications - same operating system, same processor (Intel Atom N450 is the latest processor commonly found in netbooks), same hard drive capacity, same RAM (upgradable up to 2 GB usually), etc.
It is with respect to batteries that they oftentimes differ. Batteries may either be 3-cell or 6-cell. Currently, most netbooks have 6-cell batteries. Most probably, you would not want to get a netbook with 3-cell battery only although they may be a bit cheaper. A 6-cell battery is more advisable to have in a netbook. But take note of this: even among 6-cell batteries, there may be differences in capacities. Some netbooks have 6-cell batteries with 48wh capacity while some netbooks have 6-cell batteries with 63wh capacity. Of course, the latter can run your netbook longer than the former on a single charge.
Worthy of mentioning here also is the fact that some netbooks offer 9-cell batteries. Ordinarily, this means longer runtime on battery for your netbook. However, this also means an undesirable bulge on your netbook in order to accommodate the 9-cell battery. Some people do not mind this anyway.
For netbooks, the ability to run on a battery for a longer period of time is very essential. Netbooks are meant to be carried around and used anywhere. They are not intended to be desktop replacements and to sit in one corner of your room the whole day.
If you are eyeing a particular netbook, you may want to inquire into how long the netbook can run on a single charge. Some manufacturers claim that their netbook can run for 10, 12, or 14 hours even though their batteries may be of the same capacity. This is due to the fact that netbooks today have built-in programs that allow the users to adjust the way the computer consumes power depending on how the computer is being used on a given occasion.
Once you are already satisfied with the battery, you may then proceed with your other questions about the netbook, especially about those that makes it different from the rest of the species.