If you are snacking in between meals because you are truly hungry and/or you need the energy, then that is a positive reason to snack. Make healthy choices and watch the calorie intake. If you're snacking because of stress or boredom, then this is a negative reason to snack and should be avoided. Before you choose to snack, think about why you are doing it and if it is truly necessary. Snacking is not bad if it's done for the right reasons.
Link to blog: http://thefitdivas.typepad.com/my_weblog/2009/03/snack-right.html